From jkl@ccl.net Fri Nov  8 17:02:33 1991
Date: Fri, 8 Nov 91 17:02:28 -0500
From: jkl@ccl.net
To: chemistry@ccl.net
Subject: RE: Program to calculate Franck Condon Factors
Status: R

Forwarding to the list:
jkl
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Message  4:
>From DUCHOW@UCRAC1.UCR.EDU Fri Nov  8 15:21:07 1991
Date:    Fri, 8 Nov 1991 12:21:28 -0800 (PST)
From: DUCHOW@UCRAC1.UCR.EDU (John K. Duchowski)
Subject: RE: Program to calculate Franck Condon Factors
To: chemistry-request@ccl.net

schoeffel@sc.ZIB-Berlin.DE (Schoeffel) writes:

> I would like to calculate Franck-Condon factors for absorption spectra.
> Does anybody know about "public domain" programs for
> 
> 1)fitting of potential energy hypersurfaces (and calculation of 
>   derivatives)
> 2)solution of one-dimensional vibrational schroedinger equation 
>   by both variational or numerical approach

	Well, I have a much more primitive beast from my grad school days :).
It's a two-mode program which calculates Franck-Condon factors, and then the
absorption profile for specified number of vibrational levels in the ground
and excited electronic states, for which it uses Bioltzmann weighting.  The
FC factors are obtained from Manneback's recursion relations (Phycica 1955 ?).

	I used it to calculate absorption profiles of NIR bands of porphyrinic
dimers (JACS 1990).  It's not very sophisticated but it seems to give correct
answers - I also used it to verify absorption profiles of simple polyenes where
two modes are required (Kohler, Snow, J. Phys. Chem., 1976).  It's written in
C and on PCs uses EGA graphics to display the spectrum.  The memory limitations
on PCs require smaller number of levels to be used.  However, same code on
a Unix box or a Vax/VMS can easily use ca. 15 levels in all states in both
modes.  If anyone's interested, I post it to the list.

John Duchowski
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