III.G.7. (XIII.B.3.) (XIII.D.5.) |
Compare vibrational frequencies for two calculations for SiC2 (Silicon dicarbide)
A =
HF/6-31G*
B =
MP2/6-31G*
scale factors=0.8985, 0.943
symmetry | frequency (cm-1) | reduced mass (amu) | IR Intensity (km mol-1) | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
mode number | A | B | A | B | diff. | ratio | A | B | diff. | ratio | A | B | diff. | ratio | |||
1 | A1 | A1 | 1790 | 1658 | 131.9 | 1.080 | 12.002 | 12.001 | 0.001 | 1.000 | 45.44 | 8.76 | 36.68 | 5.186 | |||
2 | A1 | A1 | 763 | 792 | -29.3 | 0.963 | 16.294 | 16.296 | -0.002 | 1.000 | 183.11 | 133.65 | 49.46 | 1.370 | |||
3 | B2 | B2 | 304i | 150 | -453.7 | -2.027 | 12.656 | 12.690 | -0.034 | 0.997 | 72.63 | 121.40 | -48.77 | 0.598 | |||
scaled by | 0.8985 | 0.943 |
See section III.C.1 List or set vibrational scaling factors
to change the scale factors used here.
See section III.C.2
Calculate a vibrational scaling factor for a given set of molecules
to determine the least squares best scaling factor.