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 H₂O₂⁺ (Hydrogen peroxide 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	Ag	Ag		3357	3214	143.5	1.045		1.075	1.073	0.002	1.002		0.00	0.00	0.00
2	Ag	Ag		1567	1493	73.5	1.049		1.178	1.155	0.023	1.020		0.00	0.00	0.00
3	Ag	Ag		1404	1009	395.6	1.392		14.398	14.828	-0.430	0.971		0.00	0.00	0.00
4	Au	Au		873	824	49.5	1.060		1.067	1.067	0.000	1.000		388.11	372.17	15.94	1.043
5	Bu	Bu		3315	5480	-2164.6	0.605		1.067	1.067	0.000	1.000		1219.06	886362.90	-885143.90	0.001
6	Bu	Bu		1290	1268	22.6	1.018		1.067	1.067	0.000	1.000		321.07	577.19	-256.12	0.556
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.