Table 3.

Assessment of computed infrared intensities for different functionals vs. experimental and high-level ab initio results. The test set consists^a of HF, CO, H₂O, HCN, C₂H₂, H₂CO, NH₃, C₂H₄, CH₂F₂, CH₄ and SiH₄. Mean error (ME), mean average error (MAE), and root mean square error (RMS) are all given in km mol⁻¹

Basis set	Method	High level ab initiob			Experimental
		ME	MAE	RMS	ME	MAE	RMS
6-31G(d)	HF	36.0	37.9	82.8	37.9	44.5	93.6
	M06-L	20.3	27.6	63.1	22.2	31.7	74.0
	LC-ωPBE	10.1	17.9	33.3	12.1	23.8	45.9
	CAM-B3LYP	7.6	16.4	28.5	9.5	21.8	41.0
	B3LYP	6.4	16.8	29.4	8.3	21.3	40.8
	HSE	7.9	15.4	27.5	9.8	20.7	39.0
	PBEh	7.7	15.3	26.9	9.6	20.7	38.6
	HCTH	2.0	18.8	30.4	3.9	20.4	38.3
	PBE	−0.1	18.5	30.4	1.9	20.4	37.2
	M06-HF	3.8	18.1	30.1	5.7	21.0	34.8
Sadlej pVTZ	HF	24.0	24.8	40.6	25.9	30.1	50.2
	M06-HF	4.2	18.9	26.4	6.2	23.0	30.2
	M06-L	4.1	10.6	16.8	6.0	12.3	22.1
	LC-ωPBE	3.2	10.7	15.7	5.2	15.8	21.8
	CAM-B3LYP	5.1	9.0	13.9	7.0	14.4	21.4
	PBE	−2.8	11.5	22.6	−0.9	11.4	21.0
	HCTH	−0.1	9.7	18.2	1.8	11.6	19.5
	PBEh	2.0	9.5	16.4	3.9	13.3	19.3
	HSE	2.2	9.2	15.8	4.1	13.1	19.1
	B3LYP	3.5	6.9	11.8	5.4	11.9	18.9
aug-cc-pVTZ	HF	25.6	26.0	43.1	27.5	30.5	52.6
	M06-HF	4.3	18.9	28.0	6.3	22.1	28.2
	LC-ωPBE	4.6	9.8	14.2	6.6	14.8	20.8
	CAM-B3LYP	6.4	8.2	12.1	8.3	14.4	20.6
	M06-L	3.1	8.7	13.6	5.1	11.8	20.4
	PBE	−1.7	11.2	21.2	0.2	10.5	19.2
	HCTH	1.6	10.0	18.2	3.5	11.0	18.9
	B3LYP	4.8	6.2	10.2	6.7	11.2	18.2
	PBEh	3.3	8.7	14.2	5.2	12.1	17.5
	HSE	3.5	8.5	13.7	5.4	11.9	17.4

^aOnly those modes for which experimental intensities were available were considered; modes that are inactive were not considered, and degenerate modes were considered only once.

^bQCISD/6-311+G(3df,3pd) for HF, CO, NH₃, C₂H₄, and CH₂F₂;²³ CCSD(T)/aug-cc-pVTZ for the rest of the set.⁶²