Alphabetic List of Keywords

Note 1: Additional components of CPMD input https that do not fit into the following list are explained in the succeeding section 11.5.

Note 2: Keywords for the &QMMM section of the CPMD/Gromos QM/MM-Interface code are not listed here but in section 9.16.2.

ACM0

Section: &DFT

Add exact exchange to the specified FUNCTIONAL according to the adiabatic connection method 0. [134,135] This only works for isolated systems and should only be used if an excessive amount of CPU time is available.

ACM1

Section: &DFT

Add exact exchange to the specified FUNCTIONAL according to the adiabatic connection method 1. [136,135] The parameter is read from the next line. This only works for isolated systems and should only be used if an excessive amount of CPU time is available.

ACM3

Section: &DFT

Add exact exchange to the specified FUNCTIONAL according to the adiabatic connection method 3. [136,135] The three needed parameters are read from the next line. This only works for isolated systems and should only be used if an excessive amount of CPU time is available.

ALEXANDER MIXING

Section: &CPMD

Mixing used during optimization of geometry or molecular dynamics. Parameter read in the next line.
Default value is 0.9

ALPHA

Section: &PATH

Smoothing parameter for iterating the string (see [128]).
Default value is 0.2

ALLTOALL {SINGLE,DOUBLE}

Section: &CPMD

Perform the matrix transpose (AllToAll communication) in the 3D FFT using single/double precision numbers. Default is to use double precision numbers.

ANDERSON MIXING $N=n$

Section: &CPMD

Anderson mixing for the electronic density during self-consistent iterations. In the next line the parameter (between 0 and 1) for the Anderson mixing is read.
Default is 0.2 .
With the additional option $N=n$ a mixing parameter can be specified for different threshold densities. $n$ different thresholds can be set. The program reads $n$ lines, each with a threshold density and an Anderson mixing parameter.

ANGSTROM

Section: &SYSTEM

The atomic coordinates and the supercell parameters and several other parameters are read in Ångstroms.
Default is atomic units which are always used internally. Not supported for QMMM calculations.

ANNEALING {IONS,ELECTRONS,CELL}

Section: &CPMD

Scale the ionic, electronic, or cell velocities every time step. The scaling factor is read from the next line.

ATOMIC CHARGES

Section: &ATOMS

Changes the default charge (0) of the atoms for the initial guess to the values read from the next line. One value per atomic species has to be given.

AVERAGED POTENTIAL

Section: &PROP

Calculate averaged electrostatic potential in spheres of radius Rcut around the atomic positions.
Parameter Rcut is read in from next line.

BECKE BETA

Section: &DFT

Change the $\beta$ parameter in Becke's exchange functional [137] to the value given on the next line.

BENCHMARK

Section: &CPMD

This keyword is used to control some special features related to benchmarks. If you want to know more, have a look in the source code.

BERENDSEN {IONS,ELECTRONS,CELL}

Section: &CPMD

Use a simple Berendsen-type thermostat[28] to control the respective temperature of ions, electrons, or cell. The target temperature and time constant $\tau$ (in a.u.) are read from the next line.

These thermostats are a gentler alternative to the TEMPCONTROL mechanism to thermalize a system. For production runs, please use the corresponding NOSE thermostats, as the Berendsen scheme does not represent any defined statistical mechanical ensemble.

BFGS

Section: &CPMD

Use a quasi-Newton method for optimization of the ionic positions. The approximated Hessian is updated using the Broyden-Fletcher-Goldfarb-Shano procedure [138].

BLOCKSIZE STATES

Section: &CPMD

Parameter read in from next line.
NSTBLK
Defines the minimal number of states used per processor in the distributed linear algebra calculations.
Default is to equally distribute states over all processors.

BOGOLIUBOV CORRECTION [OFF]

Section: &CPMD

Computes the Bogoliubov correction for the energy of the Trotter approximation or not.
Default is no Bogoliubov correction.
The keyword has to appear after FREE ENERGY FUNCTIONAL.

BROYDEN MIXING

Section: &CPMD

Parameters read in from next line.
BROYMIX, ECUTBROY, W02BROY, NFRBROY, IBRESET
These mean:

BROYMIX:

Initial mixing, e.g. $0.1$ ; default value is 0.5

ECUTBROY:

Cutoff for Broyden mixing. DUAL*ECUT is the best choice and the default

W02BROY:

$w_0^2$ parameter of Johnson [139]. Default 0.01

NFRBROY:

Number of Anderson mixing steps done before Broyden mixing. Default is 0

IBRESET:

Number of Broyden vectors. $5$ is usually a good value and the default.

You can also specify some parameters with the following syntax:
[BROYMIX=BROYMIX] [ECUTBROY=ECUTBROY]
[W02BROY=W02BROY] [NFRBROY=NFRBROY]
[IBRESET=IBRESET]
Finally, you can use the keyword DEFAULT to use the default values.

CELL {ABSOLUTE, DEGREE, VECTORS}

Section: &SYSTEM

The parameters specifying the super cell are read from the next line. Six numbers in the following order have to be provided: $a$ , $b/a$ , $c/a$ , $\cos \alpha$ , $\cos \beta$ , $\cos \gamma$ . For cubic phases, $a$ is the lattice parameter. CPMD will check those values, unless you turn off the test via CHECK SYMMETRY. With the keyword ABSOLUTE, you give $a$ , $b$ and $c$ . With the keyword DEGREE, you provide $\alpha$ , $\beta$ and $\gamma$ in degrees instead of their cosine. With the keyword VECTORS, the lattice vectors $a1$ , $a2$ , $a3$ are read from the next line instead of the 6 numbers. In this case the SYMMETRY keyword is not used.

CENTER MOLECULE [OFF]

Section: &CPMD

The center of mass is moved/not moved to the center of the computational box in a calculation with the cluster option. This is only done when the coordinates are read from the input http.

CENTROID DYNAMICS

Section: &PIMD

Adiabatic centroid molecular dynamics, see Ref. [140,141,142] for theory and details of our implementation, which yields quasiclassical dynamics of the nuclear centroids at a specified temperature of the non-centroid modes. This keyword makes only sense if used in conjunction with the normal mode propagator via the keyword NORMAL MODES and FACSTAGE $>1.0$ and WMASS $=1.0$ . The centroid adiabaticity control parameter FACSTAGE, which makes the non-centroid modes artificially fast in order to sample adiabatically the quantum fluctuations, has to be chosen carefully; note that FACSTAGE  $= 1/\gamma$ as introduced in Ref. [142] in eq. (2.51).

CG-ANALYTIC

Section: &RESP

The number of steps for which the step length in the conjugate gradient optimization is calculated assuming a quadratic functional E(2) (quadratic in the linear response vectors). No accuracy impact, pure convergence speed tuning.
Default value is 3 for NMR and 99 otherwise.

CG-FACTOR

Section: &RESP

The analytic length calculation of the conjugate-gradient step length yields in general a result that is slightly too large. This factor is used to correct for that deficiency. No accuracy impact, pure convergence speed tuning.
Default is 0.8 .

CHANGE BONDS

Section: &ATOMS

The buildup of the empirical Hessian can be affected.
You can either add or delete bonds. The number of changed bonds is read from the next line. This line is followed by the description of the bonds. The format is
{ ATOM1 ATOM2 FLAG} .
ATOM1 and ATOM2 are the numbers of the atoms involved in the bond. A FLAG of $-1$ causes a bond to be deleted and a FLAG of $1$ a bond to be added.
Example:

2
1	2	+1
6	8	-1

CHARGES

Section: &PROP

Calculate atomic charges. Charges are calculated according to the method of Hirshfeld [143] and charges derived from the electrostatic potential [144].

CHARGE

Section: &SYSTEM

The total charge of the system is read from the next line.
Default is 0 .

CHECK MEMORY

Section: &CPMD

Check sanity of all dynamically allocated arrays whenever a change in the allocation is done. By default memory is checked only at break points.

CHECK SYMMETRY [OFF]

Section: &SYSTEM

The precision with which the conformance of the CELL parameters are checked against the (supercell) SYMMETRY is read from the next line. With older versions of CPMD, redundant variables could be set to arbitrary values; now all values have to conform. If you want the old behavior back, you can turn the check off by adding the keyword OFF or by providing a negative precision. Default value is: 1.0e-4

CLASSICAL CELL [ABSOLUTE, DEGREE]

Section: &SYSTEM

Not documented.

CLASSICAL TEST

Section: &PIMD

Test option to reduce the path integral branch to the classical code for the special case $P=1$ in order to allow for a one-to-one comparison to a run using the standard branch of CPMD. It works only with primitive propagator, i.e. not together with NORMAL MODES, STAGING and/or DEBROGLIE CENTROID.

CLASSTRESS

Section: &CPMD

Not documented.

CLUSTER

Section: &SYSTEM

Isolated system such as a molecule or a cluster. Same effect as SYMMETRY 0, but allows a non-orthorhombic cell. Only rarely useful.

CMASS

Section: &CPMD

The fictitious mass of the supercell in atomic units is read from the next line.
Default value is to use the total mass of all atoms in the system.

COMPRESS [WRITEnn]

Section: &CPMD

Write the wavefunctions with nn bytes precision to the restart http.
Possible choices are WRITE32, WRITE16, WRITE8 and WRITEAO.
WRITE32 corresponds to the compress option in older versions. WRITEAO stores the wavefunction as a projection on atomic basis sets. The atomic basis set can be specified in the section &BASIS. If this input section is missing a default basis from Slater type orbitals is constructed. See section 11.5.3 for more details.

CONDUCTIVITY

Section: &PROP

Computes the optical conductivity according to the Kubo-Greenwod formula

$$\sigma(\omega) = \frac{2 \pi e^2}{3m^2 V_\mathrm{cell}} \frac{1}{... ...p}} \vert\psi _j \rangle \vert^2 \delta(\epsilon _i -\epsilon_j - \hbar \omega)$$

where $\psi _i$ are the Kohn-Sham eigenstates, $\epsilon_i$ their corresponding eigenvalues, $f_i$ the occupation number and the difference $f_i-f_j$ takes care of the fermionic occupancy. This calculation is executed when the keyword PROPERTIES is used in the section &CPMD. In the section &PROP the keyword CONDUCTIVITY must be present and the interval $\Delta \omega$ for the calculation of the spectrum is read from the next line. Note that, since this is a PROPERTIES calculation, you must have previously computed the electronic structure of your system and have a consistent RESTART http ready to use.

Further keyword: STEP=0.14, where (e.g.) 0.14 is the bin width in eV of the $\sigma(\omega)$ histogram if you want it to be different from $\Delta \omega$ . A http MATRIX.DAT is written in your working directory, where all the non-zero transition amplitudes and related information are reported (see the header of MATRIX.DAT). An example of application is given in Ref. [145].

CONFINEMENT POTENTIAL

Section: &ATOMS

The use of this label activates a spherical gaussian confinement potential in the calculation of the form factor of pseudopotentials. In the next line(s) two parameters for each atomic species must be supplied: the amplitude $\alpha$ and the cut off radius $r_c$ . The gaussian spherical amplitude is computed as $A=\pi ^{3/2}r_c^3\cdot \alpha$ and the gaussian confinement potential reads

$$V(\mathbf{G}) = \sum_\mathbf{G} A \cdot \vert\mathbf{G}\vert\cdot e^{-G^2r_c^2/4}$$

being G the G-vectors, although in practice the loop runs only on the G-shells $G=\vert\mathbf{G}\vert$ .

CONJUGATE GRADIENTS [ELECTRONS, IONS, NOPRECONDITIONING]

Section: &CPMD

For the electrons, the keyword is equivalent to PCG. The NOPRECONDITIONING parameter only applies for electrons. For the ions the conjugate gradients scheme is used to relax the atomic positions.

CONSTANT CUTOFF

Section: &SYSTEM

Apply a cutoff function to the kinetic energy term [147] in order to simulate constant cutoff dynamics. The parameters $A$ , $\sigma$ and $E_o$ are read from the next line (all quantities have to be given in Rydbergs).

$$G^2 \to G^2 + A \left[ 1 + \mbox{erf} \left( {\frac{\frac{1}{2} G^2 - E_o}{\sigma}} \right) \right]$$

CONSTRAINTS

Section: &ATOMS

With this option you can specify several constraints and restraints on the atoms. (see section 11.5.2 for more information on the available options and the input format). This section of the input has to be terminated by a line containing END CONSTRAINTS.

CONVERGENCE [ADAPT, ENERGY, CALFOR, RELAX, INITIAL]

Section: &CPMD

The adaptive convergence criteria for the wavefunction during a geometry optimization are specified. For more information, see [146]. The ratio TOLAD between the smallest maximum component of the nuclear gradient reached so far and the maximum allowed component of the electronic gradient is specified with CONVERGENCE ADAPT. This criterion is switched off once the value TOLOG given with CONVERGENCE ORBITALS is reached. By default, the adaptive gradient criterion is not active. A reasonable value for the parameter TOLAD is 0.02.
If the parameter TOLENE is given with CONVERGENCE ENERGY, in addition to the gradient criterion for the wavefunction, the energy change between two wavefunction optimization cycles must be smaller than the energy change of the last accepted geometry change multiplied by TOLENE for the wavefunction to be considered converged. By default, the adaptive energy criterion is not active. It is particularly useful for transition state search with P-RFO, where the trust radius is based on the quality of energy prediction. A reasonable value for TOLENE is 0.05.
To save CPU time, the gradient on the ions is only calculated if the wavefunction is almost converged. The parameter TOLFOR given with CONVERGENCE CALFOR is the ratio between the convergence criteria for the wavefunction and the criteria whether the gradient on the ions is to be calculated. Default value for TOLFOR is 3.0 .
If the wavefunction is very slowly converging during a geometry optimization, a small nuclear displacement can help. The parameter NSTCNV is given with CONVERGENCE RELAX. Every NSTCNV wavefunction optimization cycles, the convergence criteria for the wavefunction are relaxed by a factor of two. A geometry optimization step resets the criteria to the unrelaxed values. By default, the criteria for wavefunction convergence are never relaxed.
When starting a geometry optimization from an unconverged wavefunction, the nuclear gradient and therefore the adaptive tolerance of the electronic gradient is not known. To avoid the full convergence criterion to be applied at the beginning, a convergence criterion for the wavefunction of the initial geometry can be supplied with CONVERGENCE INITIAL. By default, the initial convergence criterion is equal to the full convergence criterion.

CONVERGENCE [ORBITALS, GEOMETRY, CELL]

Section: &CPMD

The convergence criteria for optimization runs is specified.
The maximum value for the biggest element of the gradient of the wavefunction (ORBITALS), of the ions (GEOMETRY), or the cell (CELL) is read from the next line.
Default values are 10$^{-5}$ for the wavefunction, 5$\times$ 10$^{-4}$ for the ions and 1.0 for the cell. For diagonalization schemes the first value is the biggest variation of a density component. Defaults are 10$^{-3}$ and 10$^{-3}$ .

CONVERGENCE

Section: &LINRES

Convergence criterion for linear response calculations.
Default value is 10$^{-5}$ .

CONVERGENCE

Section: &RESP

Convergence criterion on the gradient $\delta E/\delta \psi^*$ Default value is 10$^{-5}$ .

CORE SPECTRA

Section: &PROP

Computes the X-ray adsorption spectrum and related transition matrix elements according to Ref. [148]. This calculation is executed when the keyword PROPERTIES is used in the section &CPMD. In the section &PROP the keyword CORE SPECTRA must be present and the core atom number (e.g. 10 if it is the 10$th$ atom in your list) and core level energy (in au) are read from the next line, while in the following line the $n$ and $l$ quantum numbers of the selected core level, along with the exponential factor $a$ of the STO orbital for the core level must be provided. In the case of $1s$ states, the core orbital is reconstructed as

$$\psi _{1s}(r) = 2 a^{\frac{3}{2}} r \cdot \exp (-a\cdot r)$$

and it is this $a$ value in au that must be supplied in input. As a general rule, first-row elements in the neutral case have the following $a$ values: B (4.64), C (5.63), N (6.62), O (7.62). For an excited atom these values would be of course a bit larger; e.g. for O it is 7.74453, i.e. 1.6 % larger. Since this is a PROPERTIES calculation, you must have previously computed the electronic structure of your system and have a consistent RESTART http ready to use. A http XRAYSPEC.DAT is written in your working directory, containing all the square transition amplitudes and related information, part of which are also written in the standard output. Waring: in order to use this keyword you need special pseudopotentials. These are provided, at least for some elements, in the PP library of CPMD and are named as *_HOLE.psp

COUPLINGS {FD=$\epsilon$ ,PROD=$\epsilon$ } [NAT]

Section: &SYSTEM

Calculate non-adiabatic couplings [126] using finite differences (FD and PROD are two different finite-difference approximations). The displacement $\epsilon$ is expected in atomic units. If NAT=$n$ is given, the coupling vector acting on only a subset of $n$ atoms is calculated. In this case, a line containing $n$ atom sequence numbers is expected. See COUPLINGS NSURF.

COUPLINGS LINRES {BRUTE FORCE,NVECT=$n$ } [THR,TOL]

Section: &SYSTEM

Calculate non-adiabatic couplings [126] using linear-response theory. With BRUTE FORCE, the linear response to the nuclear displacements along all Cartesian coordinates is calculated. With NVECT=$n$ , at most $n$ cycles of the iterative scheme in [126] are performed. However, the iterative calculation is also stopped earlier if its contribution to the non-adiabatic coupling vector is smaller a given tolerance (TOL= $C_{\mathrm{tol}}$ ). In the case of the iterative scheme, also the option THR can be given, followed by three lines each containing a pair of a threshold contribution to the non-adiabatic coupling vector and a tolerance for the linear-response wavefunction (see [126]). Do not forget to include a &LINRES section in the input, even if the defaults are used. See COUPLINGS NSURF.

COUPLINGS NSURF

Section: &SYSTEM

Required for non-adiabatic couplings: the Kohn-Sham states involved in the transition. For the moment, only one pair of states makes sense, NSURF=1. On the following line, the orbital numbers of the two Kohn-Sham states and a weight of 1.0 are expected. For singlet-singlet transitions, the ROKS-based Slater transition-state density (LOW SPIN EXCITATION LSETS) should be used. For doublet-doublet transitions, the local spin-density approximation (LSD) with the occupation numbers (OCCUPATION, NSUP, STATES) of the corresponding Slater transition-state density should be used.

CUBECENTER

Section: &PROP

Sets the center of the cubehttps produced by the CUBEFILE flag. The next line has to contain the coordinates of the center in Bohr or Angstrom, depending on whether the ANGSTROM keyword was given. Default is the geometric center of the system.

CUBEFILE ORBITALS,DENSITY HALFMESH

Section: &PROP

Plots the requested objects in .CUBE http format. If ORBITALS are demanded, the total number as well as the indices have to be given on the next and second next line. HALFMESH reduces the number of grid points per direction by 2, thus reducing the http size by a factor of 8.

CUTOFF [SPHERICAL,NOSPHERICAL]

Section: &SYSTEM

The cutoff for the plane wave basis in Rydberg is read from the next line. The keyword SPHERICAL is used with k points in order to have $\vert g + k\vert^2 < E_{cut}$ instead of $\vert g\vert^2 < E_{cut}$ . This is the default.

DAMPING {IONS,ELECTRONS,CELL}

Section: &CPMD

Add a damping factor $f_{damp}(x) = - \gamma \cdot v(x)$ to the ionic, electronic, or cell forces in every time step. The scaling factor $\gamma$ is read from the next line. Useful values depend on the employed masses are generally in the range $5.0 \to 50.0$ .

Damping can be used as a more efficient alternative to ANNEALING for wavefunction, geometry or cell optimization (and particularly combinations thereof) of systems where the faster methods (e.g. ODIIS, PCG, LBFGS, GDIIS) fail to converge or may converge to the wrong state.

DAVIDSON DIAGONALIZATION

Section: &CPMD

Use Davidson diagonalization scheme.[149]

DAVIDSON PARAMETER

Section: &CPMD

This keyword controls the Davidson diagonalization routine used to determine the Kohn-Sham energies.
The maximum number of additional vectors to construct the Davidson matrix, the convergence criterion and the maximum number of steps are read from the next line.
Defaults are 10$^{-5}$ and the same number as states to be optimized. If the system has 20 occupied states and you ask for 5 unoccupied states, the default number of additional vectors is 25. By using less than 25 some memory can be saved but convergence might be somewhat slower.

DAVIDSON PARAMETER

Section: &TDDFT

The maximum number of Davidson iterations, the convergence criteria for the eigenvectors and the maximal size of the Davidson subspace are set. The three parameters ndavmax, epstdav, ndavspace are read from the next line.
Default values are 100 , 10$^{-10}$ and 10 .

DAVIDSON RDIIS

Section: &TDDFT

This keyword controls the residual DIIS method for TDDFT diagonalization. This method is used at the end of a DAVIDSON diagonalization for roots that are not yet converged. The first number gives the maximum iterations, the second the maximum allowed restarts, and the third the maximum residual allowed when the method is invoked.
Default values are 20 , 3 and $10^{-3}$ .

DEBROGLIE [CENTROID]

Section: &PIMD

An initial configuration assuming quantum free particle behavior is generated for each individual atom according to its physical mass at the temperature given in Kelvin on the following input line. Using DEBROGLIE each nuclear position obtained from the &ATOMS section serves as the starting point for a Gaussian Lévy walk of length $P$ in three dimensions, see e.g. Ref. [150]. Using DEBROGLIE CENTROID each nuclear position obtained from the &ATOMS section serves as the centroid (center of geometry) for obtaining the centroid (center of geometry) for obtaining the $P$ normal modes in three dimensions, see e.g. Ref. [151]. This option does only specify the generation of the initial configuration if INITIALIZATION and GENERATE REPLICAS are active. Default is DEBROGLIE CENTROID and 500 Kelvin.

DEBUG CODE

Section: &CPMD

Turn on very verbose output concerning subroutine calls for debugging purposes.

DEBUG FILEOPEN

Section: &CPMD

Turn on very verbose output concerning opening https for debugging purposes.

DEBUG FORCES

Section: &CPMD

Turn on very verbose output concerning the calculation of each contribution to the forces for debugging purposes.

DEBUG IO

Section: &CPMD

Turn on very verbose output concerning the reading and writing of restart https for debugging purposes.

DEBUG MEMORY

Section: &CPMD

Very verbose output concerning memory for debugging purpose.

DEBUG NOACC

Section: &CPMD

Do not read/write accumulator information from/to the RESTART http. This avoids putting timing information to the restart and makes restart https identical for otherwise identical runs.

DENSITY CUTOFF [NUMBER]

Section: &SYSTEM

Set the plane wave energy cutoff for the density. The value is read from the next line. The density cutoff is usually automatically determined from the wavefunction CUTOFF via the DUAL factor.
With the additional flag NUMBER the number of plane waves can be specified directly. This is useful to calculate bulk modulus or properties depending on the volume. The given energy cutoff has to be bigger than the one to have the required plane wave density number.

DIAGONALIZER {DAVIDSON,NONHERMIT,PCG} [MINIMIZE]

Section: &TDDFT

Specify the iterative diagonalizer to be used.
Defaults are DAVIDSON for the Tamm-Dancoff method, NONHERMIT (a non-hermitian Davidson method) for TDDFT LR and PCG (Conjugate gradients) for the optimized subspace method. The additional keyword MINIMIZE applies to the PCG method only. It forces a line minimization with quadratic search.
Default is not to use line minimization .

DIAGONAL [OFF]

Section: &HARDNESS

Not documented

DIFF FORMULA

Section: &LINRES

Number of points used in finite difference formula for second derivatives of exchange-correlation functionals. Default is two point central differences.

DIIS MIXING

Section: &CPMD

Use the direct inversion iterative scheme to mix density.
Read in the next line the number of previous densities (NRDIIS) for the mixing (however not useful).

DIIS MIXING [$N=n$ ]

Section: &CPMD

Like DIIS MIXING, but number of previous densities for the mixing can be specified as a function of the density.
$n$ different thresholds for the density can be set. The program reads $n$ lines with a threshold density and a NRDIIS number (number of previous densities for the mixing). Numbers NRDIIS have to increase. If the NRDIIS is equal to 0, Anderson mixing is used. Very efficient is to use Anderson mixing and subsequently DIIS mixing.

DIPOLE DYNAMICS {SAMPLE,WANNIER}

Section: &CPMD

Calculate the dipole moment [78,79] every NSTEP iteration in MD.
NSTEP is read from the next line if the keyword SAMPLE is present.
Default is every time step.
The keyword Wannier allows the calculation of optimally localized Wannier functions[85,91,123]. The procedure used is equivalent (for single k-point) to Boys localization.

The produced output is IONS+CENTERS.xyz, IONS+CENTERS, DIPOLE, WANNIER_CENTER and WANNIER_DOS. The localization procedure is controlled by the following keywords.

DIPOLE MOMENT [BERRY,RS]

Section: &PROP

Calculate the dipole moment.
Without the additional keywords BERRY or RS this is only implemented for simple cubic and fcc supercells. The keyword RS requests the use of the real-space algorithm. The keyword BERRY requests the use of the Berry phase algorithm.
Default is to use the real-space algorithm.

DISCARD [OFF,PARTIAL,TOTAL,LINEAR]

Section: &RESP

Request to discard trivial modes in vibrational analysis from linear response (both PHONON and LANCZOS).

OFF = argument for performing no projection
PARTIAL = argument for projecting out only translations (this is the default)
TOTAL = argument for projecting both rotations and translations
LINEAR = argument for projecting rotations around the $C-\infty$ axis in a linear molecule (not implemented yet).

DISTRIBUTED LINALG {ON,OFF}

Section: &CPMD

Perform linear algebra calculations using distributed memory algorithms. Setting this option ON will also enable (distributed) initialization from atomic wavefunctions using a parallel Lanczos algorithm [7]. Note that distributed initialization is not available with KPOINTS calculations. In this case, initialization from atomic wavefunctions will involve replicated calculations.

When setting LINALG ON the keyword BLOCKSIZE STATES becomes relevant (see entry). The number of BLOCKSIZE STATES must be an exact divisor of the number of STATES.

DISTRIBUTE FNL

Section: &CPMD

The array FNL is distributed in parallel runs.

DUAL

Section: &SYSTEM

The ratio between the wavefunction energy CUTOFF and the DENSITY CUTOFF is read from the next line.
Default is 4.
There is little need to change this parameter, except when using ultra-soft pseudopotentials, where the wavefunction cutoff is very low and the corresponding density cutoff is too low to represent the augmentation charges accurately. In order to maintain good energy conservation and have good convergence of wavefunctions and related parameters, DUAL needs to be increased to values of 6-10.
Warning: You can have some trouble if you use the DUAL option with the symmetrization of the electronic density.

DUMMY ATOMS

Section: &ATOMS

The definition of dummy atoms follows this keyword.
Three different kinds of dummy atoms are implemented. Type 1 is fixed in space, type 2 lies at the arithmetic mean, type 3 at the center of mass of the coordinates of real atoms.
The first line contains the total number of dummy atoms. The following lines start with the type label TYPE1, TYPE2, TYPE3.
For type 1 dummy atoms the label is followed by the Cartesian coordinates.
For type 2 and type 3 dummy atoms the first number specifies the total number of atoms involved in the definition of the dummy atom. Then the number of these atoms has to be specified on the same line. A negative number of atoms stands for all atoms. Example:

3
TYPE1	0.0	0.0	0.0
TYPE2	2	1	4
TYPE3	-1

Note: Indices of dummy atoms always start with total-number-of-atoms plus 1. In the case of a Gromos-QM/MM interface simulations with dummy hydrogen atoms for capping, it is total-number-of-atoms plus number-of-dummy-hydrogens plus 1

EIGENSYSTEM

Section: &RESP

Not documented.

ELECTRON TEMPERATURE

Section: &CPMD

The electronic temperature is read from the next line.
Default is $1000$ K.

ELECTRONIC SPECTRA

Section: &CPMD

Perform a TDDFT calculation [152,153] to determine the electronic spectra. See in section 9.9.1 and under the other keywords for the input sections &LINRES and &TDDFT for further options.

ELECTROSTATIC POTENTIAL [SAMPLE=nrhoout]

Section: &CPMD

Store the electrostatic potential on http. The resulting file is written in platform specific binary format. You can use the cpmd2cube tool to convert it into a Gaussian cube http for visualization. Note that this flag automatically activates the RHOOUT flag as well.

With the optional keyword SAMPLE the http will be written every nrhoout steps during an MD trajectory. The corresponding time step number will be appended to the httpname.

ELF [PARAMETER]

Section: &CPMD

Store the total valence density and the valence electron localization function ELF [154,155,156] on https. The default smoothing parameters for ELF can be changed optionally when specifying in addition the PARAMETER keyword. Then the two parameters ``elfcut'' and ``elfeps'' are read from the next line. The particular form of ELF that is implemented is defined in the header of the subroutine elf.F. Note: it is a very good idea to increase the plane wave cutoff and then specify ``elfcut'' $=0.0$ and ``elfeps'' $=0.0$ if you want to obtain a smooth ELF for a given nuclear configuration. In the case of a spin-polarized (i.e. spin unrestricted) DFT calculation (see keyword LSD) in addition the spin-polarized average of ELF as well as the separate $\alpha$ - and $\beta$ -orbital parts are written to the https LSD_ELF, ELF_ALPHA and ELF_BETA, respectively; see Ref. [157] for definitions and further information. Note: ELF does not make much sense when using Vanderbilt's ultra-soft pseudopotentials!

EMASS

Section: &CPMD

The fictitious electron mass in atomic units is read from the next line.
Default is 400 a.u..

ENERGY PROFILE

Section: &SYSTEM

Perform an energy prohttp calculation at the end of a wavefunction optimization using the ROKS or ROSS methods.

ENERGYBANDS

Section: &CPMD

Write the band energies (eigenvalues) for k points in the http ENERGYBANDS.

EPR options, see response_p.inc

Section: &RESP

Calculate the EPR $g$ tensor for the system. This routine accepts most, if not all, of the options available in the NMR routine (RESTART, NOSMOOTH, NOVIRTUAL, PSI0, RHO0, OVERLAP and FULL). Most important new options are:
FULL SMART: does a calculation with improved accuracy. A threshold value (between 0 and 1) must be present on the next line. The higher the threshold value, the lower the computational cost, but this will also reduce the accuracy (a bit). Typically, a value of 0.05 should be fine.
OWNOPT: for the calculation of the $g$ tensor, an effective potential is needed. By default, the EPR routine uses the local potential ( $V_{LOC} = V_{PP,LOC} + V_{HARTREE} + V_{XC}$ ). This works well with Goedecker pseudopotentials, but rather poor with Troullier-Martins pseudopotentials. When using this option, the following potential is used instead:

$$V_{EFF} = -\frac{Z}{r}\mathrm{erf}(r/r_c) + V_{HARTREE} + V_{XC}$$

and $r_c$ (greater than 0) is read on the next line.
HYP: calculates the hyperfine tensors. See epr_hyp.F for details.

Contact Reinout.Declerck@UGent.be should you require further information.

EXCHANGE CORRELATION TABLE [NO]

Section: &DFT

Specifies the range and the granularity of the lookup table for the local exchange-correlation energy and potential. The number of table entries and the maximum density have to be given on the next line.
Note that this keyword is only relevant when using OLDCODE and even then it is set to NO be default. Previous default values were 30000 and 2.0.

EXCITED DIPOLE

Section: &PROP

Calculate the difference of dipole moments between the ground state density and a density generated by differently occupied Kohn-Sham orbitals.
On the next line the number of dipole moments to calculate and the total number orbitals has to be given. On the following lines the occupation of the states for each calculation has to be given. By default the dipoles are calculated by the method used for the DIPOLE MOMENT option and the same restrictions apply. If the LOCAL DIPOLE option is specified the dipole moment differences are calculated within the same boxes.

EXTERNAL POTENTIAL {ADD}

Section: &CPMD

Read an external potential from http. With ADD specified, its effects is added to the forces acting on the ions.

EXTERNAL FIELD

Section: &SYSTEM

Applies an external electric field to the system using the Berry phase. The electric field vector in AU is read from the next line.

EXTRAPOLATE WFN {ASPC,POLY} [STORE,CSTEPS=naspc]

Section: &CPMD

Read the number of wavefunctions to retain mextra from the next line.
These wavefunctions are used to extrapolate the initial guess wavefunction in Born-Oppenheimer MD. This can help to speed up BO-MD runs significantly by reducing the number of wavefunction optimization steps needed through two effects: the initial guess wavefunction is much improved and also you do not need to converge as tightly (via setting CONVERGENCE ORBITALS) to conserve energy.

Two extrapolation algorithms are available, the ASPC has shown to yield best energy conservation and is thus the default. The order of the extrapolation is $mextra - 2$ . A simpler polynomial extrapolation POLY is also available. Here the order of the extrapolation is $mextra - 1$ .

With the additional keyword STORE the wavefunction history is also written to restart https. See RESTART for how to read it back.

With the additional keyword CSTEPS=, the number of corrector steps (SCF steps) can be limited to $naspc$ . This feature becomes active as soon as a full wavefunction history exists.

FACMASS

Section: &PIMD

Obtain the fictitious nuclear masses $M_I^\prime$ within path integral molecular dynamics from the real physical atomic masses $M_I$ (as tabulated in the DATA ATWT / .../ statement in atoms.F) by multiplying them with the dimensionless factor WMASS that is read from the following line; if the NORMAL MODES or STAGING propagator is used obtain $M_I^{\prime (s)}=$   WMASS$\cdot M_I^{(s)}$ for all replicas $s=1, \dots , P$ ; see e.g. Ref. [142] eq. (2.37) for nomenclature.
Default value of WMASS is 1.0

FACTOR

Section: &PATH

Step for propagating string (see [128]).
Default value is 1.0

FFTPARM FILE [ON,OFF]

Section: &CPMD

Controls the use of self-adapting features when the compiled in FFT library supports this. When enabled, CPMD will turn on additional runtime optimizations of the FFT library. The resulting parameters will be written to a http called FFTPARM_DATA and re-read on subsequent runs. The parameters in the http are machine specific and when moving a job to a different machine, or using a different FFT library the http should be discarded.

The use of self-adapting runtime optimizations incurs additional overhead and thus does only sometimes lead to faster execution. It is recommended to stick with the default settings unless you know what you are doing.

FILE FUSION

Section: &CPMD

Reads in two separate RESTART https for ground state and ROKS excited state and writes them into a single restart http.
Required to start SURFACE HOPPING calculations.

FILEPATH

Section: &CPMD

The path to the https written by CPMD (RESTART.x, MOVIE, ENERGIES, DENSITY.x etc.) is read from the next line. This overwrites the value given in the environment variable CPMD_FILEPATH. Default is the current directory or ``./''.

FINITE DIFFERENCES

Section: &CPMD

The step length in a finite difference run for vibrational frequencies (VIBRATIONAL ANALYSIS keywords) is read from the next line.
With the keywords COORD=coord_fdiff(1..3) and RADIUS=radius put in the same line as the step length, you can specify a sphere in order to calculate the finite differences only for the atoms inside it. The sphere is centered on the position coord_fdiff(1..3) with a radius radius (useful for a point defect).

NOTE: The the step length for the finite difference is always in Bohr (default is 1.0d-2 a.u.). The (optional) coordinates of the center and the radius are read in either Angstrom or Bohr, depending on whether the ANGSTROM keyword is specified or not.

FIXRHO UPWFN [VECT LOOP WFTOL]

Section: &CPMD

Wavefunctions optimization with the method of direct inversion of the iterative subspace (DIIS), performed without updating the charge density at each step. When the orbital energy gradients are below the given tolerance or when the maximum number of iterations is reached, the KS energies and the occupation numbers are calculated, the density is updated, and a new wavefunction optimization is started. The variations of the density coefficients are used as convergence criterion. The default electron temperature is 1000 K and 4 unoccupied states are added. Implemented also for k-points. Only one sub-option is allowed per line and the respective parameter is read from the next line. The parameters mean:

VECT:

The number of DIIS vectors is read from the next line. (ODIIS with 4 vectors is the default).

LOOP:

the minimum and maximum number of DIIS iterations per each wfn optimization is read from the following line. Default values are 4 and 20.

WFTOL:

The convergence tolerance for the wfn optimization during the ODIIS is read from the following line. The default value is $10^{-7}$ . The program adjusts this criterion automatically, depending on the convergence status of the density. As the density improves (when the density updates become smaller), also the wavefunction convergence criterion is set to its final value.

FORCE FIELD

Section: &CLASSIC

not documented.

FORCE STATE

Section: &TDDFT

The state for which the forces are calculated is read from the next line. Default is for state 1.

FREE ENERGY FUNCTIONAL

Section: &CPMD

Calculates the electronic free energy using free energy density functional [53,54,56,158] from DFT at finite temperature.
This option needs additional keywords (free energy keywords).
By default we use LANCZOS DIAGONALIZATION with Trotter factorization and BOGOLIUBOV CORRECTION. If the number of states is not specified, use $N_{electrons}/2+4$ .

FREEZE QUANTUM

Section: &CLASSIC

Freeze the quantum atoms and performs a classical MD on the others (in QMMM mode only !).

FULL TRAJECTORY

Section: &CLASSIC

Not documented

FUNCTIONAL functionals

Section: &DFT

Single keyword for setting up XC-functionals.
Available functionals are NONE, SONLY, LDA (in PADE form), BONLY, BP, BLYP, XLYP, GGA (=PW91), PBE, PBES, REVPBE, HCTH, OPTX, OLYP, TPSS, PBE0, B1LYP, B3LYP, X3LYP,PBES

FUKUI [N=nf]

Section: &RESP

Calculates the response to a change of occupation number of chosen orbitals. The indices of these orbitals are read from the following nf lines (default nf=1). The orbitals themselves are not read from any RESTART http but from WAVEFUNCTION.* https generated with RHOOUT in the &CPMD section; to recall this the orbital numbers have to be negative, just like for the RHOOUT keyword.

A weight can be associated with each orbital if given just after the orbital number, on the same line. It corresponds to saying how many electrons are put in or taken from the orbital. For example;

   FUKUI N=2
   -i 1.0
   -j -1.0

corresponds to the response to taking one electron from orbital i and put it in orbital j.

GAUGE {PARA,GEN,ALL}

Section: &LINRES

Gauge of the linear-response wavefunctions. Default is the parallel-transport gauge (PARA) for closed-shell calculations and a sensible combination of the parallel-transport gauge and the full-rotation gauge (GEN) for all other cases. The full-rotation gauge can be enforced for all states by selecting ALL. See [127].

GC-CUTOFF

Section: &DFT

On the next line the density cutoff for the calculation of the gradient correction has to be specified. The default value is $10^{-8}$ . Experience showed that for a small CUTOFF value (e.g. when using Vanderbilt pseudopotentials) a bigger values have to be used. A reasonable value for a 25 ryd cutoff calculation is $5 \cdot 10^{-6}$ .
Warning: for the HCTH functional, since it includes both the $xc$ part and the gradient correction in a unique functional, a GC-CUTOFF too high (e.g. $\geq 5 \cdot 10^{-5}$ ) could result in not including any $xc$ part with uncontrolled related consequences.

GDIIS

Section: &CPMD

Use the method of direct inversion in the iterative subspace combined with a quasi-Newton method (using BFGS) for optimization of the ionic positions [159].The number of DIIS vectors is read from the next line.
GDIIS with 5 vectors is the default method in optimization runs.

GENERATE COORDINATES

Section: &ATOMS

The number of generator atoms for each species are read from the next line.
These atoms are used together with the point group information to generate all other atomic positions. The input still has to have entries for all atoms but their coordinates are overwritten. Also the total number of atoms per species has to be correct.

GENERATE REPLICAS

Section: &PIMD

Generate quantum free particle replicas from scratch given a classical input configuration according to the keyword DEBROGLIE specification. This is the default if INITIALIZATION is active.

GRADIENT CORRECTION [functionals]

Section: &DFT

Individual components of gradient corrected functionals can be selected. Rarely needed anymore, use the FUNCTIONAL keyword instead.

Functionals implemented are for the exchange energy:
BECKE88 [137], GGAX [160] PBEX [161], REVPBEX [162], HCTH [163], OPTX [164],PBESX [165]
and for the correlation part:
PERDEW86 [167], LYP [166], GGAC [160], PBEC [161], REVPBEC [162], HCTH [163] OLYP [164],PBESC [165].
Note that for HCTH, exchange and correlation are treated as a unique functional.
The keywords EXCHANGE and CORRELATION can be used for the default functionals (currently BECKE88 and PERDEW86). If no functionals are specified the default functionals for exchange and correlation are used.

GSHELL

Section: &CPMD

Write a http GSHELL with the information on the plane waves for further use in S(q) calculations.

HAMILTONIAN CUTOFF

Section: &CPMD

The lower cutoff for the diagonal approximation to the Kohn-Sham matrix [33] is read from the next line.
Default is 0.5 atomic units.
For variable cell dynamics only the kinetic energy as calculated for the reference cell is used.

HAMILTONIAN CUTOFF

Section: &RESP

The value where the preconditioner (the approximate Greens function $(V_{kin}+V_{coul}-\epsilon_{KS})^{-1})$ is truncated. HTHRS can also be used. Default value is 0.5.

HARDNESS

Section: &RESP

Not documented.

HARMONIC REFERENCE SYSTEM [OFF]

Section: &CPMD

Switches harmonic reference system integration [33] on/off.
The number of shells included in the analytic integration is controlled with the keyword HAMILTONIAN CUTOFF.
By default this option is switched off.

HARTREE-FOCK

Section: &DFT

Do a Hartree-Fock calculation. This only works correctly for isolated systems. It should be used with care, it needs enormous amounts of CPU time.

HARTREE

Section: &DFT

Do a Hartree calculation. Only of use for testing purposes.

HESSCORE

Section: &CPMD

Calculates the partial Hessian after relaxation of the enviroment, equivalent to NSMAXP=0 (PRFO NSMAXP).

HESSIAN [DISCO,SCHLEGEL,UNIT,PARTIAL]

Section: &CPMD

The initial approximate Hessian for a geometry optimization is constructed using empirical rules with the DISCO [168] or Schlegel's [169] parametrization or simply a unit matrix is used.
If the option PARTIAL is used the initial approximate Hessian for a geometry optimization is constructed from a block matrix formed of the parametrized Hessian and the partial Hessian (of the reaction core). If the reaction core spans the entire system, its Hessian is simply copied. The keywords RESTART PHESS are required.

HFX CUTOFF

Section: &SYSTEM

Set an additional cutoff for wavefunction and density to be used in the calculation of exact exchange. Cutoffs for wavefunctions and densities are read from the next line in Rydberg units. Defaults are the same cutoffs as for the normal calculation. Only lower cutoffs than the defaults can be specified.

HTHRS

Section: &LINRES

Threshold for Hessian in preconditioner for linear response optimizations. Default is 0.5.

IMPLICIT NEWTON RAPHSON {PREC, CONTINUE, VERBOSE, ALTERNATIVE, STEP} [N=nreg]

Section: &CPMD

Not documented.

INITIALIZATION

Section: &PIMD

Provide an initial configuration for all replicas as specified either by GENERATE REPLICAS or by READ REPLICAS. This option is automatically activated if RESTART COORDINATES is not specified. It is defaulted to GENERATE REPLICAS together with DEBROGLIE CENTROID and a temperature of 500 Kelvin.

INITIALIZE WAVEFUNCTION [RANDOM, ATOMS]

Section: &CPMD

The initial guess for wavefunction optimization are either random functions or functions derived from the atomic pseudo-wavefunctions.
Default is to use the atomic pseudo-wavefunctions.

INTERACTION

Section: &RESP

Not documented.

INTERFACE {EGO,GMX} [MULLIKEN,LOWDIN,ESP,HIRSHFELD,PCGFIRST]

Section: &CPMD

Use CPMD together with a classical molecular dynamics code. CPMD and the classical MD code are run simultaneously and communicate via a http based protocol. See the file egointer.F for more details. This needs a specially adapted version of the respective classical MD code. So far, there is an interface[170,4] to the MD programs ego[171,172] and Gromacs[133].

When using the suboption PCGFIRST the code will use PCG MINIMIZE on the very first wavefunction optimization and then switch back to DIIS.

INTFILE [READ,WRITE,FILENAME]

Section: &CPMD

This keyword means Interface File and allows to select a special http name in the reading and writing stages. The http name (max 40 characters) must be supplied in the next line.

ISOLATED MOLECULE

Section: &CPMD

Calculate the ionic temperature assuming that the system consists of an isolated molecule or cluster.
Note: This keyword affects exclusively the determination of the number of dynamical degrees of freedom. This keyword does not activate the 'cluster option' SYMMETRY 0, but it is activated if SYMMETRY 0 is used unless the keyword QMMM is set as well. It allows studying an isolated molecule or cluster within periodic boundary conditions.

ISOTOPE

Section: &ATOMS

Changes the default masses of the atoms.
This keyword has to be followed by NSP lines (number of atom types). In each line the new mass (in a.m.u.) of the respective species has to be specified (in order of their definition).

ISOTROPIC CELL

Section: &SYSTEM

Specifies a constraint on the super cell in constant pressure dynamics or geometry optimization. The shape of the cell is held fixed, only the volume changes.

KEEPREALSPACE

Section: &RESP

Like the standard CPMD option, this keeps the C0 ground state wavefunctions in the direct space representation during the calculation. Can save a lot of time, but is incredibly memory intensive.

KOHN-SHAM ENERGIES [OFF,NOWAVEFUNCTION]

Section: &CPMD

Calculation of the Kohn-Sham energies and the corresponding orbitals.
The number of empty states that have to be calculated in addition to the occupied states is read from the next line.
The Kohn-Sham orbitals are stored on the http RESTART.x except if the keyword NOWAVEFUNCTION is used. In this case, the program does not allocate memory for wavefunctions for all k points. It computes eigenvalues k point per k point losing information about wavefunctions. This keyword is used for band structure calculation to compute the eigenvalues for many k points.
Default is not to calculate Kohn-Sham energies (OFF ).
Warning: The usage of this keyword needs special care (especially restarts).

KPERT [MONKHORSTPACK,SCALE]

Section: &RESP

Calculation of total energy and electronic density of states with an arbitrary number of k-points (at almost no additional computational effort). The method is based on a $\mathbf{k}\cdot \mathbf{p}-$ like approximation developed in the framework of the density functional perturbation theory [111]. For a sampling of the BZ determined by the Monkhorst-Pack algorithm, the option MONKHORSTPACK has to be specified, followed by the dimension of the mesh along the 3 reciprocal space axis $(NK_{1} , NK_{2} , NK_{3})$ . If omitted, the individual absolute coordinates of the k-points have to be given one by one in the following lines. The SCALE option allows to specify them in units of the reciprocal cell vectors.

The line after KPERT has to contain the total number of k-points $(NKPTS)$ , which have then to be given by their coordinates and the associated weights $(RK,WK)$ in the format:
$NKPTS$
$RK_{x1} \; RK_{y1} \; RK_{z1} \; WK_{1}$
$\dots$
$RK_{x NKPTS} \; RK_{y NKPTS} \; RK_{z NKPTS} \; WK_{NKPTS}$ .
Three response wavefunctions are calculated, corresponding to the three independent orientations of the k basis vectors in reciprocal space. Therefore, 3 independent optimization loops are started ($x,y$ and $z$ ), and the 3 sets of wfns are stored (you need 4 times the memory required for a standard wavefunction optimization). The second order correction to the $\Gamma$ -point total energy is calculated for the requested k-point mesh.

Further options are (each in a new line of the input http ):

WRITE_C1

the 3 sets of response wfns are stored in three separate restart https.

HAMILTONIAN

the k-dependent Hamiltonian is constructed via the second order perturbation theory approximation, and the corresponding KS energies are calculated. Due to technical reasons, for each k-point $2*NSTATE$ KS energies are calculated, however only those corresponding to occupied orbitals are reliable.

READ_C1

the response wfns are read from RESTART.P_{xyz}.

BUILD_C00

the set of k-dependent wfns (first order correction) is calculated from the unperturbed $\Gamma$ -point wfns together with the response orbitals. They are then written in a standard RESTART http. From this restart http one can perform a calculation of the Hamiltonian matrix for each kpoint and calculate the KS energies (use LANCZOS DIAGO in &CPMD and the KPOINT option ONLYDIAG in &SYSTEM. The k-point mesh must be the same used in the linear response calculation. set also NOSPHERICAL CUTOFF in &SYSTEM).

NORESTART

no RESTART http is written.

KPOINTS options

Section: &SYSTEM

With no option, read in the next line with the number of k-points and for each k-point, read the components in the Cartesian coordinates (units $2\pi/a$ ) and the weight.

MONKHORST-PACK

Read in the next line three numbers for the Monkhorst-Pack mesh. The program calculates then the special k-points. With the keyword SHIFT=kx ky kz in the same line, you can precise the constant vector shift.

SYMMETRIZED

Symmetrized special k-points mesh (useful if you use a constant vector shift).

FULL

Construct full Monkhorst-Pack mesh with only inversion symmetry. Useful for molecular dynamics simulation The keywords SYMMETRIZED FULL preserves all symmetry of Bravais lattice so there is no need to symmetrize density and forces.

SCALED

You can give k-points in reciprocal space coordinates.

BANDS

This option is to calculate the band structure.
For each line you have to specify the number of k-points for the band, the initial and the final k-point. To finish the input, put:
0 0. 0. 0. 0. 0. 0.

BLOCK=n [OPTIONS]

The block option, specifies the number of k-points in the memory. The program uses a swap http to store the wavefunctions only by default. With the following options, you can change this behavior:

ALL

Three swap https are used to store wavefunctions and others arrays related to k-points. Swap https are in the current directory or the temporary directory given by environment variable TMPDIR. The use of memory is smaller than with the above option.

CALCULATED

One swap http is used to store only wavefunctions. The other arrays related to k-points are calculated each time if needed.

NOSWAP

The wavefunctions are not swapped. This is useful to calculate eigenvalues for each k point with little memory used.
Warning: The wavefunctions calculated are irrelevant. You have to specify explicitly some other options to use it:
MAXSTEP 1 and
STORE OFF WAVEFUNCTIONS DENSITY POTENTIAL.

LANCZOS DIAGONALIZATION {ALL}

Section: &CPMD

Use Lanczos diagonalization scheme.
Default with free energy functional.

LANCZOS DIAGONALIZATION {OPT,RESET=n}

Section: &CPMD

Use Lanczos diagonalization scheme after (OPT) or periodically during (RESET=n) direct wavefunction optimization using ODIIS. The number n specifies the number of DIIS resets (ODIIS NO_RESET=nreset) due to poor progress until the wavefunction is diagonalized. This can be helpful if the wavefunction is converging very slowly.

LANCZOS PARAMETER [N=n] [ALL]

Section: &CPMD

Give four parameters for Lanczos diagonalization in the next line:

• Maximal number of Lanczos iterations (50 is enough),
• Maximal number for the Krylov sub-space (8 best value),
• Blocking dimension ( $\leq NSTATE$ , best in range 20-100) If you put a negative or zero number, this parameter is fixed by the program in function of the number of states ( $(n+1)/(int(n/100+1))$ ).
• Tolerance for the accuracy of wavefunctions
  ($10^{-8}$ otherwise $10^{-12}$ with Trotter approximation)

If n is specified, read $n-1$ lines after the first one, containing a threshold density and a tolerance. See the hints section 9.13.1 for more information.

LANCZOS [CONTINUE,DETAILS]

Section: &RESP

lanczos_dim iterations conv_threshold lanczos_dim= dimension of the vibrational d.o.f. iterations = no. of iterations desired for this run conv_threshold = threshold for convergence on eigenvectors CONTINUE = argument for continuing Lanczos diagonalization from a previous run (reads http LANCZOS_CONTINUE) DETAILS = argument for verbosity. prints a lot of stuff

LBFGS [NREM, NTRUST, NRESTT, TRUSTR]

Section: &CPMD

Use the limited-memory BFGS method (L-BFGS) for linear scaling optimization of the ionic positions. For more information, see [146]. The information about the Hessian for the quasi-Newton method employed is derived from the history of the optimization [146,173].
Only one sub-option is allowed per line and the respective parameter is read from the next line. The parameters mean:

NREM:

Number of ionic gradients and displacements remembered to approximate the Hessian. The default is either 40 or the number of ionic degrees of freedom, whichever is smaller. Values greater the number of degrees of freedom are not advisable.

NTRUST:

NTRUST=1 switches from a trust radius algorithm to a line search algorithm. The default value of 0 (trust radius) is recommended.

NRESTT:

NRESTT$>$ 0 demands a periodic reset of the optimizer every NRESTT steps. Default is 0 (no periodic reset). This option makes only sense if the ionic gradient is not accurate.

TRUSTR:

Maximum and initial trust radius. Default is 0.5 atomic units.

It can be useful to combine these keywords with the keywords PRFO, CONVERGENCE ADAPT, RESTART LSSTAT, PRINT LSCAL ON and others.

LDA CORRELATION [functional]

Section: &DFT

The LDA correlation functional is specified.
Possible functionals are NO (no correlation functional), PZ [174], VWN [175], LYP [166] and PW [176].
Default is the PZ, the Perdew and Zunger fit to the data of Ceperley and Alder [177].

LDOS

Section: &PROP

Calculate the layer projected density of states. The number of layers is read from the next line.

To use the LDOS keyword, the user must first have performed a wavefunction optimization and then restart with the PROPERTIES and LANCZOS DIAGONALIZATION keywords in the &CPMD section (and LDOS in the &PROP section).

Warning: If you use special k-points for a special structure you need to symmetrize charge density for which you must specify the POINT GROUP.

LINEAR RESPONSE

Section: &CPMD

A perturbation theory calculation is done, according to the (required) further input in the &RESP section. In the latter, one of the possible perturbation types (PHONONS, LANCZOS, RAMAN, FUKUI, KPERT, NMR, EPR, and others see section 9.10.2) can be chosen, accompanied by further options.

LOCAL DIPOLE

Section: &PROP

Calculate $numloc$ local dipole moments.
$numloc$ is read from the next line followed by two numloc lines with the format:
$xmin$ $ymin$ $zmin$
$xmax$ $ymax$ $zmax$

LOCALIZATION

Section: &TDDFT

Use localized orbitals in the TDDFT calculation. Default is to use canonical orbitals.

LOCALIZE

Section: &HARDNESS

Use localized orbitals in an orbital hardness calculation

LOCALIZE

Section: &PROP

Localize the molecular orbitals as defined through the atomic basis set.
The same localization transformation is then applied also to the wavefunctions in the plane wave basis. These wavefunction can be printed with the keyword RHOOUT specified in the &CPMD section.

LR KERNEL functional

Section: &DFT

Use another functional for the linear response kernel.

LR-TDDFT

Section: &TDDFT

Use full linear response version of TDDFT. Default is to use TAMM-DANCOFF approximation.

LSD

Section: &CPMD

Use the local spin density approximation.
Warning: Not all functionals are implemented for this option.

LOCAL SPIN DENSITY

Section: &CPMD

Use the local spin density approximation.
Warning: Not all functionals are implemented for this option.

LOW SPIN EXCITATION [ROKS,ROSS,ROOTHAAN,CAS22]

Section: &SYSTEM

Use the low spin excited state functional [125]. For ROKS calculations, see also the ROKS keyword in the &CPMD section.

LOW SPIN EXCITATION LSETS

Section: &SYSTEM

Slater transition-state density with restricted open-shell Kohn-Sham (low spin excited state). Currently works only with ROKS but not with ROSS, ROOTHAAN, or CAS22. See Ref. [127].

LSE PARAMETERS

Section: &SYSTEM

Determines the energy expression used in LSE calculatio