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

Vibrational frequency scaling factors

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

Scale factor	How many		Source
	Molecules	Vibrations
0.934 ± 0.170	31	100	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CCl4	Carbon tetrachloride	1	A1	474	459	0.969	1	1
		2	E	223	217	0.972	1	2
		3	T2	834	776	0.930	1	3
		4	T2	323	314	0.973	1	4
CH4	Methane	1	A1	3055	2917	0.955	2	5
		2	E	1583	1534	0.969	2	6
		3	T2	3177	3019	0.950	2	7
		4	T2	1358	1306	0.962	2	8
CH3NH2	methyl amine	1	A'	3546	3361	0.948	3	9
		2	A'	3107	2961	0.953	3	10
		3	A'	3025	2820	0.932	3	11
		4	A'	1688	1623	0.962	3	12
		5	A'	1524	1473	0.966	3	13
		6	A'	1478	1430	0.968	3	14
		7	A'	1200	1130	0.942	3	15
		8	A'	1087	1044	0.960	3	16
		9	A'	883	780	0.884	3	17
		10	A"	3627	3427	0.945	3	18
		11	A"	3142	2985	0.950	3	19
		12	A"	1543	1485	0.962	3	20
		13	A"	1373	1335	0.972	3	21
		14	A"	987	1195	1.210	3	22
		15	A"	307	268	0.872	3	23
HNCO	Isocyanic acid	1	A'	3736	3538	0.947	4	24
		2	A'	2367	2269	0.958	4	25
		3	A'	1358	1327	0.977	4	26
		4	A'	825	777	0.942	4	27
		5	A'	570	577	1.013	4	28
		6	A"	652	656	1.006	4	29
H2	Hydrogen diatomic	1	Σg	4422	4401	0.995	5	30
CF2	Difluoromethylene	1	A1	1301	1225	0.942	6	31
		1	A1	1194	1225	1.026	6	32
		2	A1	693	667	0.962	6	33
		2	A1	529	667	1.260	6	34
		3	B2	1207	1114	0.923	6	35
		3	B2	1385	1114	0.804	6	36
C3H4	cyclopropene	1	A1	3345	3158	0.944	7	37
		2	A1	3097	2909	0.939	7	38
		3	A1	1737	1653	0.952	7	39
		4	A1	1547	1483	0.958	7	40
		5	A1	1184	1110	0.938	7	41
		6	A1	945	905	0.958	7	42
		7	A2	1036	996	0.961	7	43
		8	A2	867	820	0.946	7	44
		9	B1	3169	2995	0.945	7	45
		10	B1	1127	1088	0.965	7	46
		11	B1	605	569	0.940	7	47
		12	B2	3296	3124	0.948	7	48
		13	B2	1100	1043	0.948	7	49
		14	B2	1066	1011	0.948	7	50
		15	B2	818	769	0.941	7	51
CS	carbon monosulfide	1	Σ	1354	1285	0.949	8	52
CH	Methylidyne	1	Σ	2873	2861	0.996	9	53
		1	Σ	3151	2861	0.908	9	54
		1	Σ	2873	3145	1.095	9	55
		1	Σ	3151	3145	0.998	9	56
		1	Σ	2873	2931	1.020	9	57
		1	Σ	3151	2931	0.930	9	58
OH	Hydroxyl radical	1	Σ	3802	3738	0.983	10	59
HCl	Hydrogen chloride	1	Σ	3028	2991	0.988	11	60
HF	Hydrogen fluoride	1	Σ	4228	4138	0.979	12	61
NH3	Ammonia	1	A1	3513	3337	0.950	13	62
		2	A1	1107	950	0.858	13	63
		3	E	3640	3444	0.946	13	64
		4	E	1702	1627	0.956	13	65
H2O	Water	1	A1	3893	3657	0.939	14	66
		2	A1	1680	1595	0.949	14	67
		3	B2	3997	3756	0.940	14	68
H2S	Hydrogen sulfide	1	A1	2743	2615	0.953	15	69
		2	A1	1221	1183	0.969	15	70
		3	B2	2758	2626	0.952	15	71
AlH3	aluminum trihydride	1	A1'	1952	1900	0.973	16	72
		2	A2"	723	698	0.965	16	73
		3	E'	1957	1883	0.962	16	74
		4	E'	798	783	0.982	16	75
PH3	Phosphine	1	A1	2438	2323	0.953	17	76
		2	A1	1031	992	0.963	17	77
		3	E	2447	2328	0.951	17	78
		4	E	1158	1118	0.966	17	79
SiH4	Silane	1	A1	2264	2187	0.966	18	80
		2	E	992	975	0.983	18	81
		3	T2	2271	2191	0.965	18	82
		4	T2	943	914	0.969	18	83
BH3	boron trihydride	2	A2"	1167	1148	0.983	19	84
		3	E'	2711	2602	0.960	19	85
		4	E'	1231	1197	0.972	19	86
PH2	Phosphino radical	1	A1	2412	2310	0.958	20	87
		2	A1	1141	1102	0.966	20	88
SiH3	silyl	1	A1	2234	2136	0.956	21	89
		2	A1	790	728	0.922	21	90
		3	E	2268	2185	0.963	21	91
		4	E	951	922	0.969	21	92
BH	Boron monohydride	1	Σ	2371	2367	0.998	22	93
NH2	Amino radical	1	A1	3415	3219	0.943	23	94
		2	A1	1571	1497	0.953	23	95
		3	B2	3508	3301	0.941	23	96
NH	Imidogen	1	Σ	3332	3283	0.985	24	97
		1	Σ	3369	3283	0.974	24	98
		1	Σ	3332	3314	0.995	24	99
		1	Σ	3369	3314	0.984	24	100
SiH	Silylidyne	1	Σ	2054	2043	0.995	25	101
SiH2	silicon dihydride	1	A1	2086	1996	0.957	26	102
		1	A1	2213	1996	0.902	26	103
		2	A1	1038	999	0.963	26	104
		2	A1	899	999	1.112	26	105
		3	B2	2084	1993	0.956	26	106
		3	B2	2272	1993	0.877	26	107
SH	Mercapto radical	1	Σ	2716	2696	0.993	27	108
PH	phosphorus monohydride	1	Σ	2378	2364	0.994	28	109
		1	Σ	2401	2364	0.985	28	110
		1	Σ	2378	2415	1.015	28	111
		1	Σ	2401	2415	1.006	28	112
		1	Σ	2378	2403	1.010	28	113
		1	Σ	2401	2403	1.001	28	114
AlH	aluminum monohydride	1	Σ	1695	1682	0.992	29	115
BH2	boron dihydride	2	A1	1026	954	0.929	30	116
AlH2	aluminum dihydride	1	A1	1865	1770	0.949	31	117
		2	A1	773	760	0.983	31	118
		3	B2	1898	1807	0.952	31	119

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.

	80
	70
	60
	50
	40
	30
	20
	10
	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