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

Compare vibrational frequencies for two calculations for C6H4F2 (1,4-difluorobenzene)

A = HF/6-31G*

B = MP2FC/6-31G*

  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   3065 3084 -18.6 0.994   1.097 1.097 -0.000 1.000   0.00 0.00 0.00  
2 Ag Ag   1643 1596 47.2 1.030   6.039 6.559 -0.520 0.921   0.00 0.00 0.00  
3 Ag Ag   1262 1239 22.9 1.019   10.646 10.335 0.312 1.030   0.00 0.00 0.00  
4 Ag Ag   1132 1121 11.1 1.010   1.123 1.110 0.013 1.012   0.00 0.00 0.00  
5 Ag Ag   841 828 12.5 1.015   6.629 6.634 -0.005 0.999   0.00 0.00 0.00  
6 Ag Ag   439 429 10.3 1.024   13.345 13.298 0.047 1.004   0.00 0.00 0.00  
7 Au Au   973 831 141.5 1.170   1.328 1.241 0.088 1.071   0.00 0.00 0.00  
8 Au Au   428 393 35.3 1.090   3.099 3.712 -0.613 0.835   0.00 0.00 0.00  
9 B1g B1g   827 751 76.2 1.102   1.243 1.243 0.000 1.000   0.00 0.00 0.00  
10 B1u B1u   3051 3071 -20.5 0.993   1.090 1.090 0.001 1.001   8.18 2.89 5.29 2.827
11 B1u B1u   1527 1487 40.6 1.027   2.989 3.056 -0.067 0.978   286.17 245.85 40.32 1.164
12 B1u B1u   1226 1190 36.7 1.031   2.819 2.657 0.162 1.061   189.87 144.01 45.86 1.318
13 B1u B1u   998 983 15.1 1.015   2.404 2.498 -0.094 0.962   2.33 3.92 -1.59 0.595
14 B1u B1u   724 711 12.6 1.018   6.271 6.241 0.031 1.005   60.55 48.44 12.11 1.250
15 B2g B2g   948 800 147.8 1.185   1.339 1.066 0.273 1.256   0.00 0.00 0.00  
16 B2g B2g   690 478 211.3 1.442   3.914 12.090 -8.176 0.324   0.00 0.00 0.00  
17 B2g B2g   377 342 34.9 1.102   7.489 8.680 -1.191 0.863   0.00 0.00 0.00  
18 B2u B2u   3064 3083 -19.0 0.994   1.097 1.097 0.000 1.000   4.71 0.12 4.58 38.346
19 B2u B2u   1413 1398 15.0 1.011   3.251 4.976 -1.725 0.653   0.15 0.68 -0.53 0.227
20 B2u B2u   1147 1367 -220.4 0.839   3.692 5.968 -2.276 0.619   0.66 0.24 0.42 2.716
21 B2u B2u   1052 1065 -13.2 0.988   1.648 1.225 0.423 1.345   18.87 12.77 6.10 1.478
22 B2u B2u   337 327 9.9 1.030   11.758 11.695 0.063 1.005   6.00 4.87 1.13 1.232
23 B3g B3g   3053 3074 -21.0 0.993   1.092 1.090 0.001 1.001   0.00 0.00 0.00  
24 B3g B3g   1627 1589 38.3 1.024   7.439 8.027 -0.588 0.927   0.00 0.00 0.00  
25 B3g B3g   1279 1244 35.3 1.028   1.290 1.273 0.017 1.013   0.00 0.00 0.00  
26 B3g B3g   628 611 17.0 1.028   7.209 7.229 -0.021 0.997   0.00 0.00 0.00  
27 B3g B3g   435 417 18.2 1.044   4.820 4.834 -0.014 0.997   0.00 0.00 0.00  
28 B3u B3u   856 764 91.8 1.120   1.635 1.544 0.091 1.059   109.96 96.46 13.50 1.140
29 B3u B3u   516 472 43.5 1.092   2.450 2.685 -0.236 0.912   8.63 8.16 0.47 1.058
30 B3u B3u   162 151 10.3 1.068   11.577 11.611 -0.034 0.997   2.59 1.60 0.99 1.616
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.