III.B.3.b. (XIII.C.2.)

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at CCSD(T)/cc-pVTZ

Scale factor	How many		Source
	Molecules	Vibrations
0.975 ± 0.021	30	61	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3036	2917	0.961	1	1
		2	E	1570	1534	0.977	1	2
		3	T2	3155	3019	0.957	1	3
		4	T2	1343	1306	0.972	1	4
H2	Hydrogen diatomic	1	Σg	4410	4401	0.998	2	5
CS	carbon monosulfide	1	Σ	1269	1285	1.012	3	6
CH	Methylidyne	1	Σ	2835	2861	1.009	4	7
		1	Σ	3109	2861	0.920	4	8
		1	Σ	2835	3145	1.109	4	9
		1	Σ	3109	3145	1.011	4	10
		1	Σ	2835	2931	1.034	4	11
		1	Σ	3109	2931	0.943	4	12
OH	Hydroxyl radical	1	Σ	3740	3738	0.999	5	13
CCl	carbon monochloride	1	Σ	866	877	1.012	6	14
HCl	Hydrogen chloride	1	Σ	3001	2991	0.997	7	15
HF	Hydrogen fluoride	1	Σ	4181	4138	0.990	8	16
NH3	Ammonia	1	A1	3471	3337	0.961	9	17
		2	A1	1112	950	0.854	9	18
		3	E	3596	3444	0.958	9	19
		4	E	1688	1627	0.964	9	20
H2O	Water	1	A1	3841	3657	0.952	10	21
		2	A1	1668	1595	0.956	10	22
		3	B2	3945	3756	0.952	10	23
F2	Fluorine diatomic	1	Σg	919	917	0.997	11	24
H2S	Hydrogen sulfide	1	A1	2717	2615	0.962	12	25
		2	A1	1204	1183	0.982	12	26
		3	B2	2733	2626	0.961	12	27
AlH3	aluminum trihydride	1	A1'	1940	1900	0.979	13	28
		2	A2"	718	698	0.972	13	29
		3	E'	1946	1883	0.967	13	30
		4	E'	792	783	0.990	13	31
PH3	Phosphine	1	A1	2412	2323	0.963	14	32
		2	A1	1018	992	0.974	14	33
		3	E	2421	2328	0.962	14	34
		4	E	1142	1118	0.979	14	35
SiH4	Silane	1	A1	2251	2187	0.972	15	36
		2	E	984	975	0.991	15	37
		3	T2	2258	2191	0.970	15	38
		4	T2	931	914	0.982	15	39
C2	Carbon diatomic	1	Σg	1846	1855	1.005	16	40
		1	Σg	1632	1855	1.137	16	41
Si2	Silicon diatomic	1	Σg	543	511	0.942	17	42
		1	Σg	562	511	0.909	17	43
BH3	boron trihydride	2	A2"	1160	1148	0.989	18	44
		3	E'	2698	2602	0.964	18	45
		4	E'	1223	1197	0.979	18	46
PH2	Phosphino radical	1	A1	2386	2310	0.968	19	47
		2	A1	1125	1102	0.980	19	48
SiH3	silyl	1	A1	2219	2136	0.963	20	49
		2	A1	775	728	0.939	20	50
		3	E	2255	2185	0.969	20	51
		4	E	941	922	0.980	20	52
BH	Boron monohydride	1	Σ	2351	2367	1.007	21	53
NH2	Amino radical	1	A1	3365	3219	0.957	22	54
		2	A1	1558	1497	0.961	22	55
		3	B2	3457	3301	0.955	22	56
NH	Imidogen	1	Σ	3266	3283	1.005	23	57
		1	Σ	3323	3283	0.988	23	58
		1	Σ	3266	3314	1.015	23	59
		1	Σ	3323	3314	0.997	23	60
SiH	Silylidyne	1	Σ	2032	2043	1.005	24	61
SiH2	silicon dihydride	1	A1	2064	1996	0.967	25	62
		1	A1	2189	1996	0.912	25	63
		2	A1	1023	999	0.977	25	64
		2	A1	886	999	1.128	25	65
		3	B2	2063	1993	0.966	25	66
		3	B2	2252	1993	0.885	25	67
SH	Mercapto radical	1	Σ	2687	2696	1.003	26	68
PH	phosphorus monohydride	1	Σ	2352	2364	1.005	27	69
		1	Σ	2373	2364	0.996	27	70
		1	Σ	2352	2415	1.027	27	71
		1	Σ	2373	2415	1.018	27	72
		1	Σ	2352	2403	1.022	27	73
		1	Σ	2373	2403	1.013	27	74
AlH	aluminum monohydride	1	Σ	1681	1682	1.001	28	75
BH2	boron dihydride	2	A1	1018	954	0.937	29	76
AlH2	aluminum dihydride	1	A1	1847	1770	0.958	30	77
		2	A1	766	760	0.993	30	78
		3	B2	1883	1807	0.959	30	79

How do we calculate the scaling factor?

Histogram of vibrational frequency ratios

Ratios greater than 1.35 are in the 1.35 bin. Ratios less than 0.7 are in the 0.7 bin.

	40
	35
	30
	25
	20
	15
	10
	5
	0
		0.70			0.75			0.80			0.85			0.90			0.95			1.00			1.05			1.10			1.15			1.20			1.25			1.30			1.35
Ratio of experimental frequency to calculated frequency