Table 6. Mean Absolute Errors (kcal/mol) for the GMTKN30-CHNOF Benchmark Set: MNDO, AM1, PMx, and OMx^a.

			method
no.	subset	N	MNDO	AM1	PM3	PM6	PM7	OM1	OM2	OM3
	overall	480	27.48	16.45	14.44	16.29	16.49	11.93	7.94	7.17
	overall*b	454	27.34	14.65	11.26	10.17	9.60	11.29	6.95	6.30
1	MB08-165	25	25.53	43.66	68.73	124.39	138.35	19.47	22.47	19.46
1	MB08-165 (corr)c	25	26.52	31.84	52.27	119.53	134.55	11.04	12.20	15.03
2	W4-08 (corr)	50	14.11	10.24	9.33	7.95	6.53	7.58	4.19	6.20
2a	W4-08woMRd (corr)	43	10.32	8.90	7.66	8.00	6.51	6.00	4.12	5.37
3	G21IP	15	24.75	28.12	20.41	35.74	32.29	22.45	12.00	11.45
4	G21EA	12	27.44	25.84	14.23	20.08	18.94	24.81	11.39	9.31
5	PA	8	12.48	12.87	16.12	18.45	21.46	4.96	14.82	11.99
6	SIE11	5	21.22	9.49	12.00	4.03	4.82	4.39	7.78	4.31
7	BHPERI	22	25.15	9.97	14.05	9.73	6.13	10.67	8.21	8.25
8	BH76	54	23.84	13.06	13.36	13.39	13.68	10.39	9.72	10.66
9	BH76RC	22	11.88	13.49	11.57	15.72	16.28	5.28	4.29	5.37
10	RSE43	34	5.00	3.55	4.02	6.10	5.83	3.74	4.31	5.24
11	O3ADD6e	6	14.90	10.57	9.87	2.03	26.84	4.01	12.24	10.97
12	G2RC	15	9.23	13.42	21.68	29.47	33.48	9.07	8.23	4.16
13	ISO34	34	7.44	6.45	4.04	3.46	2.92	4.45	4.44	4.37
14	ISOL22	18	16.76	10.25	8.27	7.41	6.55	7.99	5.31	6.05
15	DC9	7	41.46	35.75	25.99	17.39	21.94	26.38	25.02	24.69
15a	DC9woC20f	6	24.66	15.68	13.30	5.18	8.64	11.40	13.59	13.20
15b	C20g	1	142.25	156.16	102.09	90.66	101.72	116.24	93.63	93.61
16	DARC	14	13.10	4.65	5.32	3.91	4.26	4.10	7.24	4.91
17	BSR36	36	52.36	39.56	16.66	7.38	9.63	30.29	10.77	3.46
17	BSR36 (corr)h	36	56.86	44.24	18.53	14.33	17.40	35.01	7.08	1.90
18	IDISP	6	34.58	13.52	8.58	13.78	16.82	13.69	7.34	6.19
19	WATER27	27	165.05	48.62	31.61	17.81	5.78	36.09	12.28	9.19
19	WATER27 (upd)i	27	164.26	47.83	30.82	17.02	6.51	35.30	11.49	8.40
20	S22	22	16.74	6.78	5.91	3.37	0.76	5.10	3.05	3.54
21	ADIM6	6	11.37	3.14	0.48	2.78	0.22	4.30	3.13	4.09
22	PCONF	10	10.08	5.35	3.68	2.27	2.97	3.60	1.28	1.33
23	ACONF	15	1.97	0.44	0.44	0.56	0.56	0.52	0.64	0.86
24	SCONF	17	17.52	2.39	3.05	2.61	2.38	5.87	1.67	1.32

^a(corr) means that energies are obtained by removing ZPVE and thermal corrections from the SQC results (see text).

^bWithout MB08-165 and C20.

^cUpon geometry optimization, some of the artificial molecules adopted structures very different from the reference geometries so that the computed corrections may be less accurate in these cases (see text).

^dSubset W4-08 without multireference cases.

^eThe adduct O₃ + C₂H₂ is better described as an open-shell singlet at OMx-Dn.

^fSubset DC9 without C₂₀ bowl/cage isomerization energy.

^gC₂₀ bowl/cage isomerization energy.

^hFor some SQC methods the corrections suffer from large accumulation errors (see text).

ⁱReference dissociation energies of four (H₂O)₂₀ clusters were updated with more accurate values from ref (132) (see text).