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

Vibrational frequency scaling factors

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

Scale factor	How many		Source
	Molecules	Vibrations
0.953 ± 0.119	27	60	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3040	2917	0.959	1	1
		2	E	1550	1534	0.990	1	2
		3	T2	3175	3019	0.951	1	3
		4	T2	1333	1306	0.980	1	4
H2	Hydrogen diatomic	1	Σg	4383	4401	1.004	2	5
CS	carbon monosulfide	1	Σ	1243	1285	1.034	3	6
HO2	Hydroperoxy radical	1	A'	3644	3436	0.943	4	7
		2	A'	1423	1392	0.978	4	8
		3	A'	1085	1098	1.011	4	9
CH	Methylidyne	1	Σ	2811	2861	1.018	5	10
		1	Σ	3128	2861	0.915	5	11
		1	Σ	2811	3145	1.119	5	12
		1	Σ	3128	3145	1.005	5	13
		1	Σ	2811	2931	1.043	5	14
		1	Σ	3128	2931	0.937	5	15
OH	Hydroxyl radical	1	Σ	3700	3738	1.010	6	16
HCl	Hydrogen chloride	1	Σ	3015	2991	0.992	7	17
HF	Hydrogen fluoride	1	Σ	4152	4138	0.997	8	18
NH3	Ammonia	1	A1	3433	3337	0.972	9	19
		2	A1	1181	950	0.805	9	20
		3	E	3561	3444	0.967	9	21
		4	E	1686	1627	0.965	9	22
H2O	Water	1	A1	3821	3657	0.957	10	23
		2	A1	1690	1595	0.944	10	24
		3	B2	3927	3756	0.957	10	25
H2S	Hydrogen sulfide	1	A1	2727	2615	0.959	11	26
		2	A1	1206	1183	0.981	11	27
		3	B2	2749	2626	0.955	11	28
AlH3	aluminum trihydride	1	A1'	1917	1900	0.991	12	29
		2	A2"	722	698	0.967	12	30
		3	E'	1928	1883	0.976	12	31
		4	E'	791	783	0.990	12	32
PH3	Phosphine	1	A1	2411	2323	0.963	13	33
		2	A1	1034	992	0.960	13	34
		3	E	2423	2328	0.961	13	35
		4	E	1142	1118	0.979	13	36
SiH4	Silane	1	A1	2242	2187	0.975	14	37
		2	E	978	975	0.997	14	38
		3	T2	2253	2191	0.972	14	39
		4	T2	925	914	0.988	14	40
BH3	boron trihydride	2	A2"	1157	1148	0.992	15	41
		3	E'	2698	2602	0.964	15	42
		4	E'	1212	1197	0.987	15	43
PH2	Phosphino radical	1	A1	2381	2310	0.970	16	44
		2	A1	1129	1102	0.976	16	45
SiH3	silyl	1	A1	2209	2136	0.967	17	46
		2	A1	775	728	0.939	17	47
		3	E	2245	2185	0.973	17	48
		4	E	934	922	0.987	17	49
BH	Boron monohydride	1	Σ	2341	2367	1.011	18	50
NH2	Amino radical	1	A1	3317	3219	0.971	19	51
		2	A1	1564	1497	0.958	19	52
		3	B2	3414	3301	0.967	19	53
NH	Imidogen	1	Σ	3195	3283	1.027	20	54
		1	Σ	3263	3283	1.006	20	55
		1	Σ	3195	3314	1.037	20	56
		1	Σ	3263	3314	1.016	20	57
SiH	Silylidyne	1	Σ	2019	2043	1.011	21	58
SiH2	silicon dihydride	1	A1	2055	1996	0.971	22	59
		1	A1	2183	1996	0.914	22	60
		2	A1	1028	999	0.972	22	61
		2	A1	882	999	1.133	22	62
		3	B2	2053	1993	0.971	22	63
		3	B2	2245	1993	0.888	22	64
SH	Mercapto radical	1	Σ	2693	2696	1.001	23	65
PH	phosphorus monohydride	1	Σ	2339	2364	1.011	24	66
		1	Σ	2362	2364	1.001	24	67
		1	Σ	2339	2415	1.033	24	68
		1	Σ	2362	2415	1.023	24	69
		1	Σ	2339	2403	1.027	24	70
		1	Σ	2362	2403	1.018	24	71
AlH	aluminum monohydride	1	Σ	1664	1682	1.011	25	72
BH2	boron dihydride	2	A1	1030	954	0.926	26	73
AlH2	aluminum dihydride	1	A1	1822	1770	0.971	27	74
		2	A1	766	760	0.992	27	75
		3	B2	1860	1807	0.971	27	76

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.

	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