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 NO₃⁺ (nitrogen trioxide cation)

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	A1	A1		2086	1700	386.6	1.227		14.651	14.691	-0.040	0.997		321.79	333.23	-11.44	0.966
2	A1	A1		1170	992	178.2	1.180		15.913	15.894	0.018	1.001		8.96	7.93	1.03	1.130
3	A1	A1		728	609	118.5	1.194		15.787	15.759	0.028	1.002		11.52	32.48	-20.96	0.355
4	B1	B1		605	606	-1.0	0.998		14.439	14.436	0.003	1.000		23.42	10.96	12.46	2.137
5	B2	B2		983	916	67.7	1.074		14.680	14.491	0.189	1.013		14.63	129.24	-114.62	0.113
6	B2	B2		577	503	73.9	1.147		15.699	15.917	-0.218	0.986		11.69	3.05	8.63	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.