[Summary]:IR intensity

[川島 武 <JDA03546 &$at$& niftyserve.or.jp>]

 On Date: Thu, 06 Apr 1995 08:28:00 +0900, I posted the question about the
 IR intensity calculation.
 Some kind souls have sent me the comments. Here I thank them very much.
 The summary follows the original question.
 ---
 >>Dear CCL'ers
 >>
 >>We are trying to determine the orientation of the adsorbed molecules on
 >>the surface by IR using polarized light. It seems to be possible to
 calculate
 >>the intensity from each component of dipole moment derivetives, but are
 >>there any programs that can do this automatically or rather easy way?
 >>We have gaussian.
 >>
 >>Thanks in advance.
 ---
 Date: Wed, 5 Apr 1995 21:53:00 -0400 (EDT)
 From: Cheol Choi <choic &$at$& gusun.acc.georgetown.edu>
 You can easily get the dipole moment derivatives from gaussian program.
 If you do frequency calculation, you will find a lot of numbers at the
 end of output files.
 After the kerword "DipolDeriv", you will have dipole derivative w.r.t
 cartesian coordinate.
 However, if you want to calculate IR intensity using it,
 you need also transformation matrix to normal coordinates.
 Best wishs Cheol-Ho,
 Georgetown Univ.
 ---
 Date:         6 Apr 95 09:20:20 GMT
 From: Dave <TILBROOK &$at$& chem.surrey.ac.uk>
 I may have misunderstood your problem but the following would seem to
 pose a problem...
 How do you propose to carry out a Gaussian calculation for such a
 complexed system. I thought that such ab initio approaches were
 usually only applicable to small isolated systems.
 A better appraoch might be to try and model the adsorbed system using
 a MM force field which has been optimised for the prediction of
 vibrational frequencies and dipole moments. I believe MM3 and CFF91
 do this quite well.
 In my work I trying to do reliable vibrational simulation using a
 velocity autocorrelation on MD data. We are doing this using the
 dynamics module under Cerius2 (by MSI). The parameter sets still need
 tweaking a bit though. In Cerius2 you can split the VAC and power
 spectrum into its anisotropic components I am not sure if this is
 what you want.
 Perhaps you should contact MSI to find out exactly what the
 significance of these axially resolved power spectra are.
 Regards
 David Tilbrook
 **********************************************************
 David Tilbrook              *   Tel: 44 1483 300 800 x 9591
 Polymer Group,              *                        x 2617
 Chemistry Department,       *
 University of Surrey,       *   Fax: 44 1483 259 514
 Guildford, Surrey, GU2 5XH  *
 U.K.                        *
 **********************************************************
 ---
 Date: Thu, 6 Apr 1995 10:59:50 +0200 (SAST)
 From: Magan Govender - PG <GOVENDEM &$at$& che.und.ac.za>
 Dear Sir,
 As far as I am aware most programs perform
 a complete normal coordinate analysis requiring
 the dipole moment derivatives, which are summed
 and multiplied by a constant to give the intensities,
 bearing in mind the signs for each component. Some
 of the programs are Vibra by Dr.Steele, NCA, SPECTRO.
 I have the email addresses of the authors, if required
 I shall be pleased to forward them to you.
 Greetings from South Africa
 Magan
 ______________________________________________________________________
 M.G. Govender
 Centre for Theoretical and Computational Chemistry
 Dept of Chemistry
 University of Natal
 King George V Avenue
 Durban
 South Africa
 ---
  It seems to me that your idea is OK to first order; however, in order
 to get the IR adsorption lineshapes and the relative intensities
 correct, I think you'll need to consider the substrate-adsorbate
 interactions.  What kind of surface are the molecules adsorbed onto?
 Eric R Bittner
 Univ. of Texas at Austin