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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at MP2FU/aug-cc-pVTZ

Scale factor	How many		Source
	Molecules	Vibrations
0.967 ± 0.029	16	34	cccbdb

Jump to histogram

Formula	Name	Mode	Symmetry	Frequency			Count
				Theory	Experiment	ratio	molecules	vibrations
CH4	Methane	1	A1	3081	2917	0.947	1	1
		2	E	1598	1534	0.960	1	2
		3	T2	3203	3019	0.943	1	3
		4	T2	1361	1306	0.960	1	4
C2H2	Acetylene	1	Σg	3566	3374	0.946	2	5
		2	Σg	1984	1974	0.995	2	6
		3	Σu	3414	3289	0.963	2	7
		4	Πg	641	612	0.955	2	8
		5	Πu	758	730	0.964	2	9
HCN	Hydrogen cyanide	1	Σ	3494	3312	0.948	3	10
		2	Σ	2048	2089	1.020	3	11
		3	Π	704	712	1.011	3	12
CO2	Carbon dioxide	1	Σg	1341	1333	0.994	4	13
		2	Σu	2422	2349	0.970	4	14
		3	Πu	668	667	0.998	4	15
CO	Carbon monoxide	1	Σ	2137	2170	1.015	5	16
		1	Σ	2137	1743	0.816	5	17
OH	Hydroxyl radical	1	Σ	3820	3738	0.979	6	18
SO2	Sulfur dioxide	1	A1	1106	1151	1.041	7	19
		2	A1	495	518	1.046	7	20
		3	B2	1312	1362	1.038	7	21
LiH	Lithium Hydride	1	Σ	1433	1405	0.981	8	22
HCl	Hydrogen chloride	1	Σ	3057	2991	0.978	9	23
HF	Hydrogen fluoride	1	Σ	4134	4138	1.001	10	24
NH3	Ammonia	1	A1	3535	3337	0.944	11	25
		2	A1	1026	950	0.926	11	26
		3	E	3666	3444	0.939	11	27
		4	E	1668	1627	0.975	11	28
N2	Nitrogen diatomic	1	Σg	2220	2359	1.062	12	29
H2O	Water	1	A1	3849	3657	0.950	13	30
		2	A1	1623	1595	0.983	13	31
		3	B2	3971	3756	0.946	13	32
F2	Fluorine diatomic	1	Σg	1009	917	0.909	14	33
Cl2	Chlorine diatomic	1	Σg	580	560	0.965	15	34
S2	Sulfur diatomic	1	Σg	721	726	1.007	16	35
		1	Σg	684	726	1.060	16	36

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