[CPMD-list] linear response calculation

[Axel Kohlmeyer]

>>> "II" == Ivaylo Ivanov <iivanov at vitae.cmm.upenn.edu> writes:

II> Hello,
II> I'm trying to do vibrational analysis with the option LR (Linear
II> Response). The manual says that "A rule of thumb is that good results are

hi,

two remarks:

1.) VIBRATIONAL ANALYSIS LR is currently broken (and has been for
    quite some time). you can do a LINEAR RESPONSE calculation with
    &RESP PHONON &END instead. check out the vibanal subdirectory
    in the CPMD test suite.

2.) the convergence of the ground state is controlled with
    CONVERGENCE ORBITALS. the default value is good enough
    to start an MD, but you should use stricter convergence
    for phonon calculations. you should also check, whether
    you need to increase the plane wave cutoff.

best regards,
     axel.

II> obtained with a 10 times stricter convergence on the ground state orbitals
II> compared to that of the response orbitals." What is not clear to me is how
II> to change the convergence criterion for the response orbitals from the
II> default value (1.0D-5). Any suggestions would be appreciated. Thanks very
II> much in advance.

II> --Ivaylo Ivanov

II> -- 
II> Ivaylo Ivanov
II> Center for Molecular Modeling | University of Pennsylvania
II> 231 S.34 Street,              | Philadelphia,PA 19104-6323
II> tel: (215) 573 8697           | fax: (215) 573 6233
II> e-mail: iivanov at cmm.chem.upenn.edu
II> _______________________________________________
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II> http://cpmd.org/mailman/listinfo/cpmd-list



--

=======================================================================
Axel Kohlmeyer       e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.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/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.