return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Comparisons > Vibrations > Vibrations > 2 calculations

Compare vibrational frequencies for two calculations for CD4 (methane-d4)


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

scale factors=0.8985, 0.943 1.006 1.006 1.006 1.273 1.273 1.273 1.285 1.285 1.285
  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 A1 A1   2032 2933 -901.3 0.693   2.014 1.008 1.999   0.00 0.00  
2 E E   1082 1532 -450.0 0.706   2.014 1.008 1.999   0.00 0.00  
3 E E   1082 1532 -450.0 0.706   2.014 1.008 1.999   0.00 0.00  
4 T2 T2   2197 3062 -864.8 0.718   2.375 1.103 2.155   18.77 19.69 0.953
5 T2 T2   2197 3062 -864.8 0.718   2.375 1.103 2.155   18.77 19.69 0.953
6 T2 T2   2197 3062 -864.8 0.718   2.375 1.103 2.155   18.77 19.69 0.953
7 T2 T2   1010 1333 -323.2 0.758   2.463 1.178 2.091   6.52 15.99 0.407
8 T2 T2   1010 1333 -323.2 0.758   2.463 1.178 2.091   6.52 15.99 0.407
9 T2 T2   1010 1333 -323.2 0.758   2.463 1.178 2.091   6.52 15.99 0.407
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.