return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) 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 NH4Cl (Ammonium chloride)


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)   Raman Activity (Å4/u)
mode number A B   A B diff. ratio   A B diff. ratio   A B diff. ratio   A B diff. ratio
1 A1 A1   3318 3307 11.5 1.003   1.027 1.027 0.000 1.000   5.38 5.53 -0.15 0.973   104.79      
2 A1 A1   2466 2207 258.1 1.117   1.039 1.042 -0.003 0.997   1035.31 1652.86 -617.55 0.626   401.69      
3 A1 A1   1144 1151 -6.2 0.995   1.188 1.197 -0.009 0.993   199.93 134.36 65.57 1.488   0.84      
4 A1 A1   165 198 -32.3 0.836   5.384 5.154 0.230 1.045   9.77 23.59 -13.82 0.414   0.54      
5 E E   3438 3451 -12.6 0.996   1.092 1.091 0.001 1.001   10.40 15.64 -5.24 0.665   62.62      
6 E E   3438 3451 -12.6 0.996   1.092 1.091 0.001 1.001   10.40 15.64 -5.24 0.665   62.62      
7 E E   1654 1641 13.1 1.008   1.064 1.063 0.001 1.001   28.88 29.04 -0.16 0.994   10.55      
8 E E   1654 1641 13.1 1.008   1.064 1.063 0.001 1.001   28.88 29.04 -0.16 0.994   10.55      
9 E E   629 777 -148.5 0.809   1.048 1.050 -0.002 0.998   110.90 100.23 10.67 1.106   1.80      
10 E E   629 777 -148.5 0.809   1.048 1.050 -0.002 0.998   110.90 100.23 10.67 1.106   1.80      
11 E E   219 252 -32.6 0.871   1.066 1.069 -0.003 0.997   22.61 22.21 0.40 1.018   5.36      
12 E E   219 252 -32.6 0.871   1.066 1.069 -0.003 0.997   22.61 22.21 0.40 1.018   5.36      
scaled by     0.8985 0.943
19 08 20 15 07

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.