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

Vibrational frequency scaling factors

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

Scale factor	How many		Source
	Molecules	Vibrations
0.979 ± 0.025	26	57	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3041	2917	0.959	1	1
		2	E	1550	1534	0.990	1	2
		3	T2	3176	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	1261	1285	1.019	3	6
CH	Methylidyne	1	Σ	2812	2861	1.017	4	7
		1	Σ	3129	2861	0.914	4	8
		1	Σ	2812	3145	1.118	4	9
		1	Σ	3129	3145	1.005	4	10
		1	Σ	2812	2931	1.042	4	11
		1	Σ	3129	2931	0.937	4	12
OH	Hydroxyl radical	1	Σ	3701	3738	1.010	5	13
HCl	Hydrogen chloride	1	Σ	3015	2991	0.992	6	14
HF	Hydrogen fluoride	1	Σ	4154	4138	0.996	7	15
NH3	Ammonia	1	A1	3435	3337	0.972	8	16
		2	A1	1181	950	0.805	8	17
		3	E	3562	3444	0.967	8	18
		4	E	1686	1627	0.965	8	19
H2O	Water	1	A1	3822	3657	0.957	9	20
		2	A1	1690	1595	0.944	9	21
		3	B2	3928	3756	0.956	9	22
H2S	Hydrogen sulfide	1	A1	2727	2615	0.959	10	23
		2	A1	1207	1183	0.980	10	24
		3	B2	2749	2626	0.955	10	25
AlH3	aluminum trihydride	1	A1'	1918	1900	0.991	11	26
		2	A2"	722	698	0.966	11	27
		3	E'	1928	1883	0.976	11	28
		4	E'	791	783	0.990	11	29
PH3	Phosphine	1	A1	2412	2323	0.963	12	30
		2	A1	1034	992	0.959	12	31
		3	E	2423	2328	0.961	12	32
		4	E	1143	1118	0.978	12	33
SiH4	Silane	1	A1	2242	2187	0.975	13	34
		2	E	978	975	0.997	13	35
		3	T2	2254	2191	0.972	13	36
		4	T2	926	914	0.987	13	37
BH3	boron trihydride	2	A2"	1157	1148	0.991	14	38
		3	E'	2699	2602	0.964	14	39
		4	E'	1212	1197	0.987	14	40
PH2	Phosphino radical	1	A1	2382	2310	0.970	15	41
		2	A1	1129	1102	0.976	15	42
SiH3	silyl	1	A1	2209	2136	0.967	16	43
		2	A1	775	728	0.939	16	44
		3	E	2246	2185	0.973	16	45
		4	E	935	922	0.987	16	46
BH	Boron monohydride	1	Σ	2342	2367	1.010	17	47
NH2	Amino radical	1	A1	3318	3219	0.970	18	48
		2	A1	1564	1497	0.957	18	49
		3	B2	3415	3301	0.967	18	50
NH	Imidogen	1	Σ	3196	3283	1.027	19	51
		1	Σ	3264	3283	1.006	19	52
		1	Σ	3196	3314	1.037	19	53
		1	Σ	3264	3314	1.015	19	54
SiH	Silylidyne	1	Σ	2021	2043	1.011	20	55
SiH2	silicon dihydride	1	A1	2056	1996	0.971	21	56
		1	A1	2183	1996	0.914	21	57
		2	A1	1029	999	0.971	21	58
		2	A1	882	999	1.132	21	59
		3	B2	2054	1993	0.970	21	60
		3	B2	2245	1993	0.888	21	61
SH	Mercapto radical	1	Σ	2693	2696	1.001	22	62
PH	phosphorus monohydride	1	Σ	2339	2364	1.010	23	63
		1	Σ	2362	2364	1.001	23	64
		1	Σ	2339	2415	1.032	23	65
		1	Σ	2362	2415	1.022	23	66
		1	Σ	2339	2403	1.027	23	67
		1	Σ	2362	2403	1.017	23	68
AlH	aluminum monohydride	1	Σ	1665	1682	1.010	24	69
BH2	boron dihydride	2	A1	1030	954	0.926	25	70
AlH2	aluminum dihydride	1	A1	1823	1770	0.971	26	71
		2	A1	766	760	0.992	26	72
		3	B2	1861	1807	0.971	26	73

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