[CPMD-list] vibrational analysis
Ari.P.Seitsonen at iki.fi
Ari.P.Seitsonen at iki.fi
Tue Feb 11 18:55:16 CET 2003
Dear Rongjian and Holger,
There are two (rather) complicated ways of getting the IR spectrum
out of CPMD; the first one is the "traditional" one, by first
calculating the vibrational normal modes and then moving (manually,
with finite differences! There's no built-in mechanism, that is) the
atoms along those modes plus calculating the dipole moment, and
eventually fitting the the dipole, then the IR intensity is
proportional to the change in the dipole along the normal mode.
The second one is calculating the dipole-dipole autocorrelation
function along a MD trajectory a'la Silvestrelli & Parrinello (sorry,
I don't remember the reference, JCP, I think). This method yields also
the anharmonic contribution (but "only" classically, of course).
Hopefully this helps.
Greetings,
apsi
PS Hmm, strange that all the modes give zero intensity in Gaussian; I
would have thought that most of them do because of the high
symmetry, but all...
> that's not a problem of your calculation. The keyword 'VIBRATIONAL
> ANALYSIS' does not calculate intensities. I think the calculation of
> intensities is not possible in CPMD, but I don't know the 3.7
> version. The intensities in the 'VIB.log' files are zero, because
> otherwise the visualisation program could be confused.
> yours
> Holger
>
> > Dear everone,
> > I found all the IR intensities in VIB.log file are zero when I try
> > to calculation the IR of Nh4+ ion by CPMD 3.7. Also when I have to
> > calculation some other systems, I have met the same problem. So I
> > wander who can tell me how to modify my calculation?
> > Thank you !
> > Sincerely yours,
> > Rongjian
>
> > Harmonic frequencies (cm**-1), IR intensities (KM/Mole),
> > Raman scattering activities (A**4/AMU), Raman depolarization ratios,
> > reduced masses (AMU), force constants (mDyne/A) and normal coordinates:
> > 1 2 3
> > ?A ?A ?A
> > Frequencies -- 142.9800 188.9340 237.2614
> > Red. masses -- 0.0000 0.0000 0.0000
> > Frc consts -- 0.0000 0.0000 0.0000
> > IR Inten -- 0.0000 0.0000 0.0000
> > Raman Activ -- 0.0000 0.0000 0.0000
> > Depolar -- 0.0000 0.0000 0.0000
> > Atom AN X Y Z X Y Z X Y Z
> > 1 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
> > 2 1 0.00 -0.35 -0.50 -0.35 0.00 0.00 -0.50 0.00 0.00
> > 3 1 0.00 -0.35 0.50 -0.35 0.00 0.00 0.50 0.00 0.00
> > 4 1 0.00 0.35 0.00 0.35 0.00 0.50 0.00 -0.50 0.00
> > 5 1 0.00 0.35 0.00 0.35 0.00 -0.50 0.00 0.50 0.00
> > 4 5 6
> > ?A ?A ?A
> > Frequencies -- 1424.1173 1425.3566 1439.0028
> > Red. masses -- 0.0000 0.0000 0.0000
> > Frc consts -- 0.0000 0.0000 0.0000
> > IR Inten -- 0.0000 0.0000 0.0000
> > Raman Activ -- 0.0000 0.0000 0.0000
> > Depolar -- 0.0000 0.0000 0.0000
> > Atom AN X Y Z X Y Z X Y Z
> > 1 7 0.00 -0.38 0.00 -0.38 0.00 0.00 0.00 0.00 -0.38
> > 2 1 0.00 0.13 0.30 0.57 0.00 0.00 0.00 0.30 0.35
> > 3 1 0.00 0.13 -0.30 0.57 0.00 0.00 0.00 -0.30 0.35
> > 4 1 0.00 0.57 0.00 0.14 0.00 0.30 0.30 0.00 0.35
> > 5 1 0.00 0.57 0.00 0.13 0.00 -0.30 -0.30 0.00 0.35
> > 7 8 9
> > ?A ?A ?A
> > Frequencies -- 1659.8740 1663.5970 3252.0807
> > Red. masses -- 0.0000 0.0000 0.0000
> > Frc consts -- 0.0000 0.0000 0.0000
> > IR Inten -- 0.0000 0.0000 0.0000
> > Raman Activ -- 0.0000 0.0000 0.0000
> > Depolar -- 0.0000 0.0000 0.0000
> > Atom AN X Y Z X Y Z X Y Z
> > 1 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
> > 2 1 0.50 0.00 0.00 0.00 -0.29 -0.41 0.00 0.41 -0.29
> > 3 1 -0.50 0.00 0.00 0.00 0.29 -0.41 0.00 -0.41 -0.29
> > 4 1 0.00 -0.50 0.00 0.29 0.00 0.41 -0.40 0.00 0.29
> > 5 1 0.00 0.50 0.00 -0.29 0.00 0.41 0.40 0.00 0.29
> > 10 11 12
> > ?A ?A ?A
> > Frequencies -- 3348.2276 3350.0631 3352.6946
> > Red. masses -- 0.0000 0.0000 0.0000
> > Frc consts -- 0.0000 0.0000 0.0000
> > IR Inten -- 0.0000 0.0000 0.0000
> > Raman Activ -- 0.0000 0.0000 0.0000
> > Depolar -- 0.0000 0.0000 0.0000
> > Atom AN X Y Z X Y Z X Y Z
> > 1 7 0.00 0.29 0.00 0.29 0.00 0.00 0.00 0.00 -0.29
> > 2 1 0.00 -0.55 0.40 0.01 0.00 0.00 0.00 -0.39 0.27
> > 3 1 0.00 -0.55 -0.40 0.01 0.00 0.00 0.00 0.39 0.26
> > 4 1 0.00 0.01 0.00 -0.55 0.00 0.40 -0.40 0.00 0.27
> > 5 1 0.00 0.01 0.00 -0.55 0.00 -0.40 0.40 0.00 0.27
> > Normal termination of Gaussian 98.
>
> --
> =======================================================================
> Holger Langer e-mail: holger.langer at theochem.ruhr-uni-bochum.de
> Lehrstuhl fuer Theoretische Chemie Phone: ++49 (0)234/32-26754
> Ruhr-Universitaet Bochum - NBCF 03/297 Fax: ++49 (0)234/32-14045
> D-44780 Bochum http://www.theochem.ruhr-uni-bochum.de
> =======================================================================
>
>
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--
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Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
Tel +41 1 635 44 97 / Fax +41 1 635 68 38 / GSM +41 79 719 09 35
Anschrift: Physikalisch Chemisches Institut (PCI), Universität Zürich (UniZh)
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