National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
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XX	H-bond dimers
XXI	Oddities

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

Compare vibrational frequencies for two calculations for ZnCN (Zinc monocyanide)

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)
mode number	A	B		A	B	diff.	ratio		A	B	diff.	ratio		A	B	diff.	ratio
1	Σ	Σ		2225	3474	-1248.7	0.641		12.799	12.813	-0.014	0.999		18.32	1111.03	-1092.71	0.016
2	Σ	Σ		385	424	-38.7	0.909		16.978	16.954	0.025	1.001		66.77	63.17	3.60	1.057
3	Π	Π		161	37i	198.1	-4.390		12.643	12.644	-0.001	1.000		2.32	4.97	-2.65	0.467
4	Π	Π		161	37i	198.1	-4.390		12.643	12.644	-0.001	1.000		2.32	4.97	-2.65	0.467
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.