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

Vibrational frequency scaling factors

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

Scale factor	How many		Source
	Molecules	Vibrations
0.927 ± 0.122	27	60	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3086	2917	0.945	1	1
		2	E	1598	1534	0.960	1	2
		3	T2	3206	3019	0.942	1	3
		4	T2	1372	1306	0.952	1	4
H2	Hydrogen diatomic	1	Σg	4422	4401	0.995	2	5
CS	carbon monosulfide	1	Σ	1379	1285	0.932	3	6
HO2	Hydroperoxy radical	1	A'	3856	3436	0.891	4	7
		2	A'	1520	1392	0.916	4	8
		3	A'	1238	1098	0.887	4	9
CH	Methylidyne	1	Σ	2891	2861	0.990	5	10
		1	Σ	2891	3145	1.088	5	11
		1	Σ	2891	2931	1.014	5	12
OH	Hydroxyl radical	1	Σ	3841	3738	0.973	6	13
HCl	Hydrogen chloride	1	Σ	3060	2991	0.978	7	14
HF	Hydrogen fluoride	1	Σ	4279	4138	0.967	8	15
NH3	Ammonia	1	A1	3560	3337	0.937	9	16
		2	A1	1108	950	0.857	9	17
		3	E	3685	3444	0.935	9	18
		4	E	1717	1627	0.948	9	19
H2O	Water	1	A1	3947	3657	0.926	10	20
		2	A1	1691	1595	0.943	10	21
		3	B2	4048	3756	0.928	10	22
H2S	Hydrogen sulfide	1	A1	2777	2615	0.942	11	23
		2	A1	1237	1183	0.957	11	24
		3	B2	2790	2626	0.941	11	25
AlH3	aluminum trihydride	1	A1'	1964	1900	0.967	12	26
		2	A2"	728	698	0.958	12	27
		3	E'	1968	1883	0.957	12	28
		4	E'	803	783	0.976	12	29
PH3	Phosphine	1	A1	2469	2323	0.941	13	30
		2	A1	1042	992	0.952	13	31
		3	E	2476	2328	0.940	13	32
		4	E	1172	1118	0.954	13	33
SiH4	Silane	1	A1	2285	2187	0.957	14	34
		2	E	1002	975	0.973	14	35
		3	T2	2290	2191	0.957	14	36
		4	T2	954	914	0.958	14	37
BH3	boron trihydride	2	A2"	1173	1148	0.978	15	38
		3	E'	2725	2602	0.955	15	39
		4	E'	1238	1197	0.967	15	40
PH2	Phosphino radical	1	A1	2436	2310	0.948	16	41
		2	A1	1152	1102	0.957	16	42
SiH3	silyl	1	A1	2250	2136	0.949	17	43
		2	A1	800	728	0.910	17	44
		3	E	2283	2185	0.957	17	45
		4	E	959	922	0.961	17	46
BH	Boron monohydride	1	Σ	2381	2367	0.994	18	47
NH2	Amino radical	1	A1	3453	3219	0.932	19	48
		2	A1	1580	1497	0.948	19	49
		3	B2	3544	3301	0.932	19	50
NH	Imidogen	1	Σ	3354	3283	0.979	20	51
		1	Σ	3354	3314	0.988	20	52
SiH	Silylidyne	1	Σ	2065	2043	0.989	21	53
SiH2	silicon dihydride	1	A1	2102	1996	0.950	22	54
		2	A1	1047	999	0.954	22	55
		3	B2	2099	1993	0.950	22	56
SH	Mercapto radical	1	Σ	2742	2696	0.983	23	57
PH	phosphorus monohydride	1	Σ	2394	2364	0.987	24	58
		1	Σ	2394	2415	1.009	24	59
		1	Σ	2394	2403	1.004	24	60
AlH	aluminum monohydride	1	Σ	1699	1682	0.990	25	61
BH2	boron dihydride	2	A1	1031	954	0.925	26	62
AlH2	aluminum dihydride	1	A1	1874	1770	0.944	27	63
		2	A1	777	760	0.978	27	64
		3	B2	1906	1807	0.948	27	65

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.

	45
	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