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

Compare vibrational frequencies for two calculations for N2O4 (Dinitrogen tetroxide)

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 Ag Ag   1450 1331 119.4 1.090   15.224 15.152 0.071 1.005   0.00 0.00 0.00  
2 Ag Ag   862 754 108.8 1.144   15.051 15.183 -0.132 0.991   0.00 0.00 0.00  
3 Ag Ag   414 238 176.6 1.742   15.546 15.481 0.064 1.004   0.00 0.00 0.00  
4 Au Au   59 99 -40.1 0.593   15.995 15.995 0.000 1.000   0.00 0.00 0.00  
5 B1u B1u   1386 1213 172.8 1.142   15.321 15.396 -0.075 0.995   435.23 385.92 49.31 1.128
6 B1u B1u   794 689 105.1 1.153   15.162 15.089 0.073 1.005   223.10 219.49 3.61 1.016
7 B2g B2g   807 597 209.6 1.351   14.266 14.291 -0.025 0.998   0.00 0.00 0.00  
8 B2u B2u   1831 1867 -35.4 0.981   14.616 14.619 -0.003 1.000   1197.44 209.55 987.89 5.714
9 B2u B2u   334 182 152.2 1.837   15.922 15.919 0.003 1.000   0.10 0.20 -0.10 0.505
10 B3g B3g   1807 1837 -30.2 0.984   14.506 14.594 -0.088 0.994   0.00 0.00 0.00  
11 B3g B3g   578 447 130.5 1.292   15.581 15.507 0.074 1.005   0.00 0.00 0.00  
12 B3u B3u   534 375 159.7 1.426   14.555 14.555 0.000 1.000   46.11 9.08 37.03 5.077
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.