[CPMD-list] PIMD AND OPENMP

[Axel Kohlmeyer]

On Sun, 8 Aug 2004, A.Alaka wrote:

AA> I think the problem I posted earlier had more to do with not being able 
AA> to read  the occupation and eigenvalues from the restart file. This is a 
AA> problem I have posted about before. I.e the occupation and eigenvalues 
AA> being absent from a restart file after a wavefunction optimisation.
AA> Has anyone else had this problem? This is all the more surprising 
AA> because I get the same problem when using (slightly) modified test input 

so what _is_ the slight modification? perhaps _that_ is 
causing the problem.

AA> files. I've done previous calculations on clusters without this problem. 
AA> Any ideas?

to read the eigenvalues and fermi energy from the restart, you first 
have to compute them (trivial but true), either by doing a KOHN-SHAM 
ENERGIES calculation _after_ the wavefunction optimization (see the 
b2h6 example in the cpmd-test distribution), or by directly doing a 
diagonalization (and setting STATES properly).

to get reasonable results with cpmd, you need to be (somewhat) careful 
and know (at least to some degree) what you are doing. cpmd is _not_ 
some kind of gaussian for plane-wave-pseudopotentials program, where
you can specify some random options and (frequently) get something
halfway decent. in fact, even for gaussian this is only true for
'conventional' cases. the similar setup for cpmd are calculations
of bulk systems with a reasonably large band gap, using norm-conserving 
pseudopotentials, with only the gamma-point, not using any transition 
metals, lanthanoids, etc. and doing only wavefunction optimization,
geometry optimization of CP-MD.

regards,
	axel.

AA> 
AA> Thanks in advance.
AA> 
AA> _______________________________________________
AA> CPMD-list mailing list
AA> CPMD-list at cpmd.org
AA> http://cpmd.org/mailman/listinfo/cpmd-list
AA> 
AA> 

-- 


=======================================================================
Dr. Axel Kohlmeyer                        e-mail: axel.kohlmeyer at rub.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================