Table 1.

Comparison between VPT2 anharmonic frequencies and the ones estimated with the anharmonic scaling scheme based on the Duschinsky transformation. ImH denotes neutral imidazole, ImH⁺ is the radical cation. Note that the optimized structure for the triplet state of imidazole has a different symmetry with respect to the singlet; the symmetry labels therefore do not apply in this case.

		ImH S0 (Cs)		ImH+ D0 (Cs)				ImH T0 (C1)
#	Sym	Harm	VPT2	Harm	VPT2	Dusch.	% dev	Harm	VPT2	Dusch.	% dev
1	A″	540	533	496	491	487	0.78	201	137	196	43.14
2	A″	647	633	544	531	534	0.73	404	328	394	20.15
3	A″	683	673	707	690	694	0.70	467	392	455	16.00
4	A″	743	724	799	778	781	0.42	599	545	586	7.42
5	A′	827	810	825	806	810	0.57	736	611	719	17.80
6	A″	885	864	890	872	871	0.20	809	775	793	2.25
7	A′	908	895	923	907	908	0.14	832	801	815	1.86
8	A″	946	932	936	917	913	0.42	914	865	892	3.14
9	A′	1073	1049	964	942	944	0.26	916	871	895	2.75
10	A′	1093	1069	1043	1018	1021	0.24	1008	966	982	1.72
11	A′	1144	1121	1125	1105	1100	0.47	1049	1025	1024	0.05
12	A′	1159	1133	1212	1186	1184	0.21	1107	1074	1080	0.58
13	A′	1286	1261	1265	1242	1237	0.45	1262	1232	1229	0.25
14	A′	1363	1323	1295	1270	1267	0.22	1305	1271	1272	0.11
15	A′	1427	1389	1416	1365	1380	1.12	1358	1317	1322	0.40
16	A′	1499	1470	1453	1415	1421	0.41	1396	1346	1366	1.45
17	A′	1556	1524	1539	1494	1506	0.79	1541	1507	1501	0.37
18	A′	3242	3115	3235	3112	3109	0.09	3110	2988	2984	0.13
19	A′	3244	3118	3241	3116	3115	0.04	3180	3054	3055	0.05
20	A′	3272	3145	3248	3124	3122	0.05	3230	3083	3105	0.69
21	A′	3652	3484	3565	3399	3401	0.07	3467	3223	3325	3.17