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NIST Standard Reference Database 101
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III.G.7. (XIII.B.3.) (XIII.D.5.)

Compare vibrational frequencies for two calculations for C4H6O (Furan, 2,3-dihydro-)

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 A   3100 3127 -27.1 0.991   1.109 1.107 0.003 1.002   14.85 5.71 9.13 2.599
2 A A   3074 3103 -28.6 0.991   1.089 1.089 -0.000 1.000   1.69 2.08 -0.39 0.811
3 A A   2965 3019 -54.3 0.982   1.109 1.105 0.004 1.004   60.43 28.02 32.41 2.156
4 A A   2921 2980 -58.7 0.980   1.067 1.100 -0.033 0.970   74.03 19.17 54.86 3.862
5 A A   2905 2931 -26.3 0.991   1.099 1.067 0.032 1.030   19.94 40.94 -21.01 0.487
6 A A   2880 2920 -39.4 0.987   1.063 1.065 -0.002 0.998   55.78 31.01 24.77 1.799
7 A A   1671 1599 72.0 1.045   5.527 5.422 0.105 1.019   76.72 40.63 36.09 1.888
8 A A   1510 1485 24.8 1.017   1.103 1.105 -0.002 0.998   0.43 0.28 0.15 1.563
9 A A   1483 1465 17.4 1.012   1.102 1.102 0.001 1.001   0.19 0.34 -0.15 0.553
10 A A   1402 1358 43.9 1.032   1.530 1.530 -0.001 1.000   6.17 2.42 3.75 2.546
11 A A   1315 1290 25.0 1.019   1.519 1.448 0.072 1.050   5.38 4.48 0.90 1.200
12 A A   1299 1263 35.1 1.028   1.333 1.321 0.013 1.010   7.79 6.20 1.59 1.257
13 A A   1236 1201 35.3 1.029   1.092 1.235 -0.143 0.884   2.30 14.36 -12.06 0.160
14 A A   1197 1172 25.1 1.021   1.232 1.267 -0.035 0.972   9.48 12.50 -3.02 0.759
15 A A   1157 1123 34.3 1.031   1.831 1.432 0.399 1.279   100.52 47.84 52.68 2.101
16 A A   1083 1058 24.9 1.024   2.127 2.176 -0.049 0.977   64.55 27.40 37.15 2.356
17 A A   1066 1041 25.1 1.024   1.562 1.837 -0.275 0.850   3.91 28.72 -24.81 0.136
18 A A   988 981 7.0 1.007   2.977 2.372 0.605 1.255   23.58 4.60 18.98 5.122
19 A A   954 917 36.8 1.040   1.348 2.773 -1.425 0.486   0.75 11.81 -11.06 0.063
20 A A   924 913 11.4 1.012   2.573 2.320 0.253 1.109   40.20 33.49 6.71 1.200
21 A A   897 841 55.9 1.066   2.753 1.331 1.422 2.069   19.30 5.34 13.96 3.611
22 A A   823 825 -2.5 0.997   1.583 1.733 -0.150 0.914   3.48 7.43 -3.96 0.468
23 A A   813 794 18.4 1.023   3.200 5.099 -1.899 0.628   6.30 6.69 -0.39 0.942
24 A A   738 684 54.3 1.079   1.195 1.212 -0.017 0.986   36.45 34.15 2.30 1.067
25 A A   685 632 53.2 1.084   4.468 2.951 1.517 1.514   2.61 1.58 1.03 1.656
26 A A   441 426 15.6 1.037   2.418 2.611 -0.193 0.926   25.50 24.03 1.47 1.061
27 A A   59 154 -95.0 0.384   1.994 1.981 0.014 1.007   2.74 2.10 0.65 1.308
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.