III.G.7. (XIII.B.3.) (XIII.D.5.) |
Compare vibrational frequencies for two calculations for HCCCN+ (Cyanoacetylene 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 | 3154 | 4010 | -855.7 | 0.787 | 1.132 | 7.743 | -6.612 | 0.146 | 201.13 | 4145.41 | -3944.28 | 0.049 | |||
2 | Σ | Σ | 1807 | 3100 | -1292.6 | 0.583 | 7.492 | 1.230 | 6.262 | 6.093 | 100.07 | 36.56 | 63.52 | 2.738 | |||
3 | Σ | Σ | 1542 | 2339 | -797.0 | 0.659 | 11.713 | 6.193 | 5.520 | 1.891 | 428.74 | 718.23 | -289.50 | 0.597 | |||
4 | Σ | Σ | 848 | 897 | -48.9 | 0.945 | 8.842 | 8.957 | -0.116 | 0.987 | 43.99 | 148.50 | -104.51 | 0.296 | |||
5 | Π | Π | 829 | 925 | -95.9 | 0.896 | 1.367 | 1.278 | 0.088 | 1.069 | 12.83 | 27.92 | -15.09 | 0.460 | |||
6 | Π | Π | 631 | 719 | -88.7 | 0.877 | 1.292 | 10.332 | -9.040 | 0.125 | 64.38 | 13.56 | 50.82 | 4.747 | |||
7 | Π | Π | 440 | 609 | -169.0 | 0.722 | 7.781 | 11.807 | -4.026 | 0.659 | 3.81 | 0.12 | 3.69 | 30.870 | |||
8 | Π | Π | 432 | 436 | -3.9 | 0.991 | 6.899 | 1.309 | 5.589 | 5.269 | 9.34 | 41.05 | -31.71 | 0.228 | |||
9 | Π | Π | 201 | 244 | -42.7 | 0.825 | 5.327 | 5.426 | -0.098 | 0.982 | 0.02 | 0.49 | -0.47 | 0.033 | |||
10 | Π | Π | 200 | 240 | -39.3 | 0.836 | 6.179 | 4.652 | 1.527 | 1.328 | 0.22 | 0.43 | -0.21 | 0.514 | |||
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.