III.G.7. (XIII.B.3.) (XIII.D.5.) |
Compare vibrational frequencies for two calculations for HNC+ (hydrogen isocyanide cation)
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 | Σ | Σ | 3399 | 3504 | -105.0 | 0.970 | 1.133 | 1.295 | -0.162 | 0.875 | 526.58 | 899.75 | -373.17 | 0.585 | |||
2 | Σ | Σ | 1956 | 2653 | -697.3 | 0.737 | 6.524 | 3.788 | 2.736 | 1.722 | 26.66 | 55.79 | -29.13 | 0.478 | |||
3 | Π | Π | 613 | 745 | -132.3 | 0.823 | 1.303 | 1.311 | -0.008 | 0.994 | 165.76 | 168.00 | -2.25 | 0.987 | |||
4 | Π | Π | 613 | 745 | -132.3 | 0.823 | 1.303 | 1.311 | -0.008 | 0.994 | 165.76 | 168.00 | -2.25 | 0.987 | |||
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.