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["Ke" <Ke@fukui.kyoto-u.ac.jp>]

Hi,

 

In my opinion, anaddb may not handle this problem.

 

(1) Two years ago, I think, a French guy used the periodical DFT

   (combining force constants) to compute the IR intensity successfully.

   It seems that the dipole moment should be computed for each displacement.

   Please search his publications (in French)

   http://catalyse.univ-lyon1.fr/index.htm

 

 

(2) Alternatively, you can turn on DFT molecular dynamics at NVE (better) or

    NVT ensemble for long time simulations (2 ps?). After that, you can use

    the

    velocity auto-correlation function (VAF) and Fourier transfer to obtain

    almost exact IR spectrum, which can compare with experiment directly.

    Probably, this is easy way for you. Only thing it needs a lot of

    computing time. It is popular for classical MD.

    I think you can search the related information easily in website.

 

Good luck.

Ke

  

__________

Fukui Instit. for Fundamental Chemistry

Kyoto University,

 

 

 

-----Original Message-----
From: timothy.french@yale.edu [mailto:timothy.french@yale.edu]
Sent: Thursday, June 24, 2004 11:14 PM
To: forum@abinit.org
Subject: [abinit-forum] IR Spectrum

 

Hello all

I am a PhD student in chemistry attempting to use ABINIT to generate calculated IR spectra of crystalline materials.  I can get the phonon frequencies (a la tutorial 5.5), but is there any way to get their IR intensities?  For anyone familiar with Gaussian, I am basically looking for the output of an "freq" calculation--something with which a stick spectrum can be created.  Would the "anaddb" utility help with that?  I've searched through all of the documentation on the website (tutorials, help file, "new user guide", past posts on this site, etc.), but to no avail.  Any help or leads in the right direction would be greatly appreciated.

Thanks in advance

-Tim