|Posted on Monday, April 21, 2014 - 4:09 pm: |
I have been running some Geometry Optimizations and Vibration Frequencies calculations for simple molecules (CO2, H2O, and SF6) for class, and have noticed what appear to be errors in reporting the results.
The raw output appears to be correct, but in the View Results window when running MOPAC2012, the lowest frequency is listed with an intensity of exactly 0, with the calculated intensities for the vibrational *levels* listed directly afterwards for the following normal modes until the values for the calculated intensities are all reported, at which point intensities for the remaining normal modes are reported as exactly 0. For example, for SF6 the first normal mode has an intensity of 0, the next six normal modes have the order of intensities reported for the six vibrational levels in the raw output (with any degeneracy ignored), and the remaining 8 normal modes with intensities of exactly 0 It appears that the view window is not accounting for degeneracy when reporting out the MOPAC intensity results.
Running SF6 in GAMESS with Oh point group symmetry, the intensities are reported out properly for the various normal modes, but the IR's of the normal modes are not reported, even though they are in the raw output and the MOs are reported with the proper IRs.
Post Number: 394
|Posted on Monday, April 21, 2014 - 10:55 pm: |
The MOPAC parsing issue is a bug and will be fixed in the next release.
In terms of GAMESS, can you please send me the output file? Typically GAMESS does not (correctly) report the symmetry of the vibrational mode unless you MANUALLY specify the symmetry of the molecule and use the "unique atom" input format. WebMO doesn't do this, and thus GAMESS usually says all vibrations are "A" symmetry. Perhaps this has changed?