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 NO3+ (nitrogen trioxide cation)


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

scale factors=0.8985, 0.943 0.189 -0.218
  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   2086 1700 386.6 1.227   14.651 14.691 -0.040 0.997   321.79 333.23 0.966
2 A1 A1   1170 992 178.2 1.180   15.913 15.894 0.018 1.001   8.96 7.93 1.130
3 A1 A1   728 609 118.5 1.194   15.787 15.759 0.028 1.002   11.52 32.48 0.355
4 B1 B1   605 606 -1.0 0.998   14.439 14.436 0.003 1.000   23.42 10.96 2.137
5 B2 B2   983 916 67.7 1.074   14.680 14.491 1.013   14.63 129.24 0.113
6 B2 B2   577 503 73.9 1.147   15.699 15.917 0.986   11.69 3.05 3.828
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.