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

Vibrational frequency scaling factors

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

Scale factor	How many		Source
	Molecules	Vibrations
0.947 ± 0.119	27	60	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3055	2917	0.955	1	1
		2	E	1557	1534	0.985	1	2
		3	T2	3188	3019	0.947	1	3
		4	T2	1342	1306	0.973	1	4
H2	Hydrogen diatomic	1	Σg	4383	4401	1.004	2	5
CS	carbon monosulfide	1	Σ	1317	1285	0.975	3	6
HO2	Hydroperoxy radical	1	A'	3679	3436	0.934	4	7
		2	A'	1452	1392	0.958	4	8
		3	A'	1133	1098	0.969	4	9
CH	Methylidyne	1	Σ	2827	2861	1.012	5	10
		1	Σ	2827	3145	1.112	5	11
		1	Σ	2827	2931	1.037	5	12
OH	Hydroxyl radical	1	Σ	3726	3738	1.003	6	13
HCl	Hydrogen chloride	1	Σ	3028	2991	0.988	7	14
HF	Hydrogen fluoride	1	Σ	4173	4138	0.992	8	15
NH3	Ammonia	1	A1	3461	3337	0.964	9	16
		2	A1	1178	950	0.807	9	17
		3	E	3586	3444	0.960	9	18
		4	E	1694	1627	0.960	9	19
H2O	Water	1	A1	3846	3657	0.951	10	20
		2	A1	1696	1595	0.940	10	21
		3	B2	3951	3756	0.951	10	22
H2S	Hydrogen sulfide	1	A1	2743	2615	0.953	11	23
		2	A1	1216	1183	0.972	11	24
		3	B2	2763	2626	0.950	11	25
AlH3	aluminum trihydride	1	A1'	1923	1900	0.988	12	26
		2	A2"	725	698	0.962	12	27
		3	E'	1933	1883	0.974	12	28
		4	E'	794	783	0.987	12	29
PH3	Phosphine	1	A1	2427	2323	0.957	13	30
		2	A1	1041	992	0.953	13	31
		3	E	2438	2328	0.955	13	32
		4	E	1152	1118	0.971	13	33
SiH4	Silane	1	A1	2251	2187	0.972	14	34
		2	E	983	975	0.992	14	35
		3	T2	2260	2191	0.969	14	36
		4	T2	932	914	0.981	14	37
BH3	boron trihydride	2	A2"	1161	1148	0.989	15	38
		3	E'	2705	2602	0.962	15	39
		4	E'	1216	1197	0.984	15	40
PH2	Phosphino radical	1	A1	2397	2310	0.964	16	41
		2	A1	1138	1102	0.968	16	42
SiH3	silyl	1	A1	2219	2136	0.963	17	43
		2	A1	782	728	0.931	17	44
		3	E	2253	2185	0.970	17	45
		4	E	940	922	0.981	17	46
BH	Boron monohydride	1	Σ	2351	2367	1.007	18	47
NH2	Amino radical	1	A1	3344	3219	0.963	19	48
		2	A1	1571	1497	0.953	19	49
		3	B2	3438	3301	0.960	19	50
NH	Imidogen	1	Σ	3219	3283	1.020	20	51
		1	Σ	3219	3314	1.030	20	52
SiH	Silylidyne	1	Σ	2032	2043	1.005	21	53
SiH2	silicon dihydride	1	A1	2069	1996	0.965	22	54
		1	A1	2196	1996	0.909	22	55
		2	A1	1036	999	0.964	22	56
		2	A1	888	999	1.125	22	57
		3	B2	2066	1993	0.965	22	58
		3	B2	2255	1993	0.884	22	59
SH	Mercapto radical	1	Σ	2709	2696	0.995	23	60
PH	phosphorus monohydride	1	Σ	2356	2364	1.003	24	61
		1	Σ	2356	2415	1.025	24	62
		1	Σ	2356	2403	1.020	24	63
AlH	aluminum monohydride	1	Σ	1671	1682	1.007	25	64
BH2	boron dihydride	2	A1	1033	954	0.923	26	65
AlH2	aluminum dihydride	1	A1	1830	1770	0.967	27	66
		2	A1	770	760	0.988	27	67
		3	B2	1867	1807	0.968	27	68

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