From BALLY@CFRUNI52.bitnet Tue Apr 6 07:54:04 1993 Message-Id: <199304061058.AA07505@oscsunb.ccl.net> Date: Tue, 6 Apr 93 12:58 N From: Subject: IR intensities from SQM force fields To: CHEMISTRY@ccl.net Dr. El-Azhari >I noticed that no one calculates the ir intensities of the SQM force fields, >but I do not know why. Also I do not have a program to do this calculation >from the SQM force field. Calculating IR intensities from the (cartesian) dipole moment derivatives (DMD's) supplied by most standard Q.M. programs these days is no problem. The very same B-matrix which is used to transform cartesian into internal coordi- nates (IC's), and whose inverse is used to transform the Hessian into force constants along IC's can also be used to transform cartesian DMD's (called atomic polar tensors in many textbooks) into DMD's along the same IC's. In the SQM force field procedure, normal coordinates (NC's) are expressed in IC's and similarly the DMD's along NC's (the quantities which are related to the IR intensities) can be expressed as sums of contributions of DMD's along IC's, so if the composition of a NC in therms of IC's varies in the course of the scaling, the corresponding DMD's vary along. Since there is virtually no additional computational effort involved, we rountinely do the transformation of atomic polar tensors in our SQM force field analyses (a paper describing our technique is due to appear in J. Phys. Chem at the end of this month, watch out for butadiene and it's radical cation). We have adapted the UMAT/BMAT routines of McIntosh and Peterson accordingly and since we do most of our calculations with Gaussian, our programs can directly read the Gaussian archive files and extract the necessary information for the SQM force field calculations. The only thing we have to supply are the defi- nitions of the internal coordinates. The reason why most people don't bother with DDM's is, that their relation to observed IR intensities is nowhere as straightforward as that of the frequen- cies, both on a conceptual level (there are several ways to calculate IR inten- sities) as well as on a practical one. In our experience, the IR intesities which appear in the SQM force fields can at best serve as a very qualitative indication, i.e. if you want to correlate a weak band in your spectrum with a certain normal mode and the predicted intensity is huge, then there is probably something wrong, and vice versa. However, quantitative correlations are impos- sible at the SCF level. It has been shown that one must go to much higher levels of theory befor one can expect anything really useful. If you are interested I can send you a copy of the thesis of the student who initiated our SQM force field program. Our code is really not in distribution shape at all, but it is available to anyone who is willing to put up with its idiosyncrasies and does not expect much support from us. I hope that this answers your questions. Best wishes thomas bally ------------------------------------------------------------------------------ | Prof. Thomas Bally | E-mail: BALLY@CFRUNI52 | | Institute for Physical Chemistry | | | University of Fribourg | Tel: 011-41-37 826 489 | | Perolles | FAX: 011-41-37 826 488 | | CH-1700 FRIBOURG | | | Switzerland | | ------------------------------------------------------------------------------ From rossi@watson.ibm.com Tue Apr 6 08:22:30 1993 Message-Id: <9304061722.AA19825@sandcastle.watson.ibm.com> To: Subject: Re: IR intensities from SQM force fields Date: Tue, 06 Apr 93 13:22:30 -0500 From: "Angelo R. Rossi (914-945-2834)" Dear Professor Bally: I read your recent note regarding IR intensities from SQM force fields. Would it be possible for me to obtain a copy of the program you mentioned as well as a copy of the thesis. If the thesis were in postscript format and there were an anonymous ftp site, then it would be easy to obtain. This is a burden for you, and I was hoping to not make it so. Would you consider putting both at the OSU repository, i.e anonymous ftp site? Best regards, A. R. Rossi From topper@haydn.chm.uri.edu Tue Apr 6 11:20:28 1993 Date: Tue, 6 Apr 93 15:20:28 -0400 From: topper@haydn.chm.uri.edu (Robert Q. Topper) Message-Id: <9304061920.AA02942@haydn.chm.uri.edu> To: CHEMISTRY@ccl.net Subject: electronic thesis archives With respect to A.R. Rossi's recent posting: > I read your recent note regarding IR intensities from SQM force > fields. Would it be possible for me to obtain a copy of the program > you mentioned as well as a copy of the thesis. If the thesis were in > postscript format and there were an anonymous ftp site, then it would > be easy to obtain. This is a burden for you, and I was hoping to not > make it so. Would you consider putting both at the OSU repository, > i.e anonymous ftp site? I think that an anonymous ftp site for scientific dissertations to be submitted electronically would be a wonderful use of disk space. This way people could pick up dissertations without the need to order hard copies (which is expensive and takes time), and thus facilitate the transmission of a lot of technical information which often goes unpublished. Postscript would be a reasonable format to use, considering that even most TeX-ers have the ability to translate their .dvi files into postscript. Any comments? Volunteers? Or perhaps this already exists? -robert ******************************** * Robert Q. Topper, Ph.D. * * Department of Chemistry * * University of Rhode Island * * Kingston, RI 02881 USA * ******************************** * topper@haydn.chm.uri.edu * * (401) 792-2597 [office] * * (401) 792-5072 [FAX] * ******************************** "And the lonely voice of youth cries...what is truth?" -Johnny Cash From dave@carbon.chem.csiro.au Wed Apr 7 05:38:42 1993 Message-Id: <199304070038.AA02951@shark.mel.dit.csiro.au> Date: Wed, 7 Apr 93 10:38:42 EST From: (Dr.) Dave Winkler Subject: Re: FTPable PS versions of theses To: chemistry@ccl.net I would also like to support the idea of making theses available by FTP. What would the average size of a compressed PS thesis be? I recently downloaded a compressed SNNS manual of 225 pages or so and it was about 6MB. The easiest way to do this would be for libraries to acquire the PS version of theses published in their institition (it is a requirement of most instititions to lodge at least one copy of a new thesis with the library anyway). As most libraries have online catalogs, maybe they could set up FTP archives too. One of the larger institutions in each area/state/country could also act as a central archive, if setting up FTP archives at each library was too hard. Cheers, Dave __________________________________________________________________________ Dr. David A. Winkler Voice: 61-3-542-2244 Principal Research Scientist Fax: 61-3-543-8160 CSIRO Division of Chemicals and Polymers Private Bag 10 Clayton, Australia. "Life is what happens to you while you're making other plans"