## III.G.7. (XIII.B.3.) (XIII.D.5.) |

# Compare vibrational frequencies for two calculations
for CCl_{2} (dichloromethylene)

### 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 | A_{1} |
A_{1} |
712 | 726 | -13.7 | 0.981 | 14.292 | 14.208 | 0.084 | 1.006 | 48.84 | 42.67 | 6.17 | 1.145 | |||

2 | A_{1} |
A_{1} |
330 | 334 | -3.9 | 0.988 | 29.461 | 29.825 | -0.365 | 0.988 | 0.02 | 0.27 | -0.25 | 0.075 | |||

3 | B_{2} |
B_{2} |
760 | 746 | 13.4 | 1.018 | 13.847 | 13.854 | -0.007 | 1.000 | 427.87 | 470.28 | -42.42 | 0.910 | |||

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.