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Select one single species if you want to do a calculation on this species in detail. You can visualize single mode contributions and play around with anharmonic parameters to see how much anharmonicity amounts to.
Select more than one species if you want to calculate the heat of reaction. You will be asked for the stoichiometric coefficients later; for now, just select all the products and reactants. Depending on your browser, you might have to press the CONTROL key together with the mouse button in order to select a second species in the same input field.
The main paper explaining the algorithms used here is J. Comp. Chem. Vol. 26, Iss. 14, pp 1438 – 1451 (online). Chemical implications of anharmonicity in silicon hydrides have been published in J. Phys. Chem. A, Vol. 106, No. 31, 2002, pp 7204 – 7215 (online). Compact and short information is found in my poster presented at the Third European Conference of Computational Chemistry (Budapest, 2000); an A4 version is available here (PDF, 9 pages, 310 kbytes). Screen rendering as done by Adobe Acrabat is bad, but printing should be OK.
My PhD thesis which explains the treatment of anharmonicity in great detail can be downloaded here as PDF file (sorry, German only). Choose either the thesis in regular size or the thesis in reduced size and print on A4 paper. If you want to read it on screen, it is far better to use Ghostscript instead of Acrobat Reader; for printing, both programs are equally well suited.
To make full use of this web site, you need a JavaScript-enabled browser understanding HTML 4.0. If your browser falls short this requirement, some navigational help has to be sacrified. You will still be able to access all the information, though.
There are problems with some versions (failed 6.10 Windows, passed 6.12 Linux) of the Opera browser, as it is confused by the OPTGROUP tag which is part of the HTML 4.0 specification. There is a page written for Opera users that avoids OPTGROUP and thus circumvents the bug: index_opera. Opera useres, please turn on JavaScript in order to be forwarded to that page automatically.
To visualize molecular vibrations, you need MOLDEN, a molecular structure and orbital drawing program. For academic use, molden is freely available for almost any common platform (Unix and Windows); it just needs an X server on your local machine (which might be the bottleneck if you live in a Microsoft environment).
Simple plots of thermodynamic functions are generated online by Gnuplot. Some of the very oldest browsers might have problems rendering the PNG graphic files. For resolution-independent printing, graphics can also be prepared in PostScript or PDF formats. To view or print these pictures, you will need additional software, e.g., Ghostscript or Adobe Acrobat Reader.
For a fine plot of thermodynamic functions, I offer fragments of Mathematica notebooks where the output of the run may be pasted to. Mathematica, however, is not free.
This site runs under an Apache Web server under SuSE Linux. The thermochemistry program is written in Fortran 90 and is compiled using the NAG Fortran 95 compiler (again, this is not free software). It contains some code from GAMESS-US in the parts dealing with internal coordinates and Hessian diagonalization.
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Address any comments, complaints or questions to Gernot Katzer