National Institute of Standards and Technology

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

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

Compare vibrational frequencies for two calculations for CH₃NH₃ (methyl ammonium radical)

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		2925	2966	-41.0	0.986		1.031	1.030	0.001	1.001		35.05	29.16	5.89	1.202
2	A1	A1		2460	2433	26.5	1.011		1.047	1.042	0.005	1.005		46.76	59.52	-12.76	0.786
3	A1	A1		1359	1296	63.3	1.049		1.173	1.154	0.018	1.016		44.69	100.76	-56.07	0.444
4	A1	A1		1134	1095	38.9	1.036		1.553	1.643	-0.091	0.945		33.91	29.91	4.00	1.134
5	A1	A1		878	819	59.2	1.072		2.214	2.136	0.078	1.037		58.54	23.57	34.97	2.483
6	A2	A2		275	280	-5.2	0.981		1.008	1.008	0.000	1.000		0.00	0.00	0.00
7	E	E		3007	3071	-64.3	0.979		1.106	1.105	0.001	1.001		12.13	12.00	0.12	1.010
8	E	E		3007	3071	-64.3	0.979		1.106	1.105	0.001	1.001		12.13	12.00	0.12	1.010
9	E	E		1472	2085	-613.0	0.706		1.051	1.154	-0.103	0.911		9.11	1248.05	-1238.95	0.007
10	E	E		1472	2085	-613.0	0.706		1.051	1.154	-0.103	0.911		9.11	1248.05	-1238.95	0.007
11	E	E		1312	1456	-143.7	0.901		1.082	1.059	0.024	1.022		1154.38	6.78	1147.60	170.327
12	E	E		1312	1456	-143.7	0.901		1.082	1.059	0.024	1.022		1154.38	6.78	1147.60	170.327
13	E	E		1219	1186	33.3	1.028		1.376	1.144	0.232	1.203		60.29	3.69	56.59	16.326
14	E	E		1219	1186	33.3	1.028		1.376	1.144	0.232	1.203		60.29	3.69	56.59	16.326
15	E	E		862	1009	-146.6	0.855		1.061	1.156	-0.095	0.918		10.54	181.17	-170.63	0.058
16	E	E		862	1009	-146.6	0.855		1.061	1.156	-0.095	0.918		10.54	181.17	-170.63	0.058
17	E	E		1601i	822	-2422.2	-1.948		1.056	1.060	-0.004	0.996		20713.01	18.60	20694.42	1113.806
18	E	E		1601i	822	-2422.2	-1.948		1.056	1.060	-0.004	0.996		20713.01	18.60	20694.42	1113.807
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.