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

# Compare vibrational frequencies for two calculations
for HBr^{-} (hydrogen bromide anion)

### 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 | 135 | 182 | -47.2 | 0.740 | 1.021 | 1.021 | 0.000 | 1.000 | 10.47 | 31.54 | -21.07 | 0.332 | |||

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.