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Compare vibrational frequencies for two calculations for C2H4N2S2 (Ethanedithioamide)


A = HF/6-31G*
B = MP2/6-31G*

scale factors=0.8985, 0.943 -0.392 0.993 -0.164 0.182 3.206 0.464
  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   3530 3497 33.5 1.010   1.104 1.101 0.003 1.003   0.00 0.00  
2 Ag Ag   3395 3329 65.5 1.020   1.048 1.049 -0.001 0.999   0.00 0.00  
3 Ag Ag   1636 1579 56.4 1.036   1.425 1.817 0.784   0.00 0.00  
4 Ag Ag   1402 1392 10.5 1.008   3.170 2.177 1.456   0.00 0.00  
5 Ag Ag   1332 1278 53.8 1.042   2.831 2.995 0.945   0.00 0.00  
6 Ag Ag   947 923 24.3 1.026   1.906 1.934 -0.028 0.986   0.00 0.00  
7 Ag Ag   644 653 -9.2 0.986   6.868 6.686 1.027   0.00 0.00  
8 Ag Ag   408 409 -1.2 0.997   3.675 3.610 0.065 1.018   0.00 0.00  
9 Ag Ag   319 328 -8.4 0.974   13.448 10.242 1.313   0.00 0.00  
10 Au Au   639 617 21.8 1.035   1.068 1.051 0.017 1.016   0.45 4.25 0.106
11 Au Au   579 447 131.5 1.294   1.384 1.474 -0.090 0.939   507.43 405.53 1.251
12 Au Au   384 368 16.6 1.045   3.368 2.903 1.160   25.92 58.97 0.439
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.