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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at ROHF/3-21G

Scale factor	How many		Source
	Molecules	Vibrations
0.907 ± 0.178	35	56	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CF3	Trifluoromethyl radical	1	A1	1160	1089	0.939	1	1
		2	A1	709	701	0.989	1	2
		3	E	1451	1260	0.868	1	3
		4	E	520	509	0.978	1	4
HCO	Formyl radical	1	A'	3026	2434	0.805	2	5
		2	A'	2030	1868	0.920	2	6
		3	A'	1249	1081	0.865	2	7
HO2	Hydroperoxy radical	1	A'	3780	3436	0.909	3	8
		2	A'	1496	1392	0.930	3	9
		3	A'	1136	1098	0.966	3	10
CH	Methylidyne	1	Σ	2886	2861	0.991	4	11
		1	Σ	2886	3145	1.090	4	12
		1	Σ	2886	2931	1.015	4	13
OH	Hydroxyl radical	1	Σ	3633	3738	1.029	5	14
NF2	Difluoroamino radical	1	A1	1119	1075	0.961	6	15
		2	A1	543	573	1.055	6	16
		3	B2	1094	942	0.861	6	17
CF	Fluoromethylidyne	1	Σ	1331	1308	0.983	7	18
CCl	carbon monochloride	1	Σ	630	877	1.391	8	19
OClO	Chlorine dioxide	1	A1	655	946	1.443	9	20
		2	A1	295	448	1.516	9	21
		3	B2	909	1110	1.221	9	22
SiF	silicon monofluoride	1	Σ	928	857	0.924	10	23
SiN	Silicon nitride	1	Σ	1245	1151	0.925	11	24
LiO	lithium oxide	1	Σ	929	815	0.877	12	25
BS	boron sulfide	1	Σ	1199	1180	0.984	13	26
AlS	Aluminum sulfide	1	Σ	571	617	1.081	14	27
CP	Carbon monophosphide	1	Σ	1335	1240	0.928	15	28
NaO	sodium monoxide	1	Σ	536	492	0.918	16	29
BeF	Beryllium monofluoride	1	Σ	1402	1247	0.890	17	30
PH2	Phosphino radical	1	A1	2350	2310	0.983	18	31
		2	A1	1222	1102	0.902	18	32
SiH3	silyl	1	A1	2269	2136	0.941	19	33
		2	A1	818	728	0.890	19	34
		3	E	2288	2185	0.955	19	35
		4	E	992	922	0.929	19	36
NH2	Amino radical	1	A1	3413	3219	0.943	20	37
		2	A1	1708	1497	0.877	20	38
		3	B2	3509	3301	0.941	20	39
NH	Imidogen	1	Σ	3233	3283	1.015	21	40
		1	Σ	3233	3314	1.025	21	41
SiH	Silylidyne	1	Σ	2032	2043	1.005	22	42
BeCl	beryllium chloride	1	Σ	801	847	1.057	23	43
SO	Sulfur monoxide	1	Σ	1136	1151	1.013	24	44
SH	Mercapto radical	1	Σ	2596	2696	1.039	25	45
SiCl	Clorosilylidyne	1	Σ	432	536	1.239	26	46
PH	phosphorus monohydride	1	Σ	2298	2364	1.028	27	47
		1	Σ	2298	2415	1.051	27	48
		1	Σ	2298	2403	1.045	27	49
MgH	magnesium monohydride	1	Σ	1587	1493	0.941	28	50
BH2	boron dihydride	2	A1	1112	954	0.858	29	51
AlH2	aluminum dihydride	1	A1	1922	1770	0.921	30	52
		2	A1	781	760	0.973	30	53
		3	B2	1938	1807	0.932	30	54
MgF	Magnesium monofluoride	1	Σ	798	712	0.892	31	55
MgCl	magnesium monochloride	1	Σ	441	462	1.048	32	56
ClO	Monochlorine monoxide	1	Σ	796	854	1.072	33	57
S2	Sulfur diatomic	1	Σg	635	726	1.142	34	58
ClS2	Sulfur chloride	1	A'	469	662	1.413	35	59
		2	A'	431	450	1.044	35	60
		3	A'	180	196	1.090	35	61

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.

	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