|
|
Contact Frank
Oellien or Wolf-D. Ihlenfeldt
for bug reports,
| |
comments and questions. Last Change: 2005-03-29
|
|
ComSpec3D is an online service for the calculation and
visualization of Infrared and Raman spectra and corresponding normal modes.
ComSpec3D stands for Computed Spectral Data
3D-Visualization.
The service will visualize IR/Raman spectra and 3D animated VRML scenes
of normal vibrations of any reasonable structure you input.
All data related to the IR and raman spectra like frequencies and normal modes are based on quantum-mechanical calculations
performed with the semi-empircal programm VAMP (PM3 method).
Because intensity peaks calculated by
semi-empirical calculations are represented at to high wavenumbers, we have added
a corection factor of 0.98 in this service. Although we have added this scoring
factor, C=O bonds still are occurring at to high wavenumbers. Therefore, we have added
another scoring factor (0.9) within the wavenumber range between 2100 and 1900 cm
-1 to address this problem.
There are two steps in this procedure. After calculating the spectral data the first display shows a GIF of the IR and Raman spectra (Figure 1) and also a table of the important wavenumbers and IR/Raman intensities.
Figure 1
After clicking on a wavenumber the vibration display will open. It shows an animated VRML scene of the corresponding normal mode (Figure 2).
Netscape 4.0 or higher or MS Internet Explorer 4.0 or higher, VRML 2.0 plugin; e.g. Octaga
For the input of chemical structures the service uses the JME Molecular Editor by Peter Ertl (Novartis). |
|
VAMP |
The spectral data are computed by the the semi-empiric program VAMP (Tim Clark, University of Erlangen) with the AM1 Hamiltonian. |
This service was developed within the framework of the ChemVis research project.
You can use the animations generated by this
service free of charge for every purpose you can imagine.
If you put them on a Web site, the HTML document
embedding the VRML file
must contain a link to this page. A small footnote is sufficient. After
some bad experiences with other
free data
we provided to the Internet community, you
are explicitly forbidden to include these scenes in any CD
or other medium you charge for without prior
contact
and an agreement in writing.
We will treat the structures confidentially, but they travel
unencrypted on the Internet, and we log them to evaluate
program performance.
Last published: 29.03.2005, FOellien |
© 2005 Computer-Chemie-Centrum, University of Erlangen-Nuremberg |