TABLE VI.

Harmonic and anharmonic vibrational frequencies (in cm⁻¹) and IR intensities (in km/mol) of C₆H₅.

Mode	Symmetry	B3LYP/SNSD				CCSD(T)/VTZ		CC/DFT		Exp.a		Assignmentb
		ω	I harm	Δ ν	Δ Ianh	ω	I harm	ν	I anh	ν	I
1	A1	3191	8.4	−132	8.50	3209	5.6	3077	14.1	3086	3.1	υ 2
2	A1	3179	3.9	−132	−3.38	3198	6.7	3066	3.3	3072	0.2	υ 20a
3	A1	3159	0.8	−137	0.75	3174	0.4	3037	1.2	3037	0.2	υ 7b
4	A1	1572	1.3	−41	−0.21	1611	0.8	1569	0.6	1581(1497c)	2.2	υ 8a
5	A1	1468	7.2	−31	0.21	1482	8.8	1451	9.0	1441	8.7	υ 19a
6	A1	1172	0.1	−15	−0.01	1179	0.1	1165	0.1	1154	0.1	υ CH scissor
7	A1	1047	8.4	−21	−1.23	1055	7.5	1035	6.3	1027	7.9	υ 18a
8	A1	1015	0.4	−15	0.30	1034	0.3	1019	0.6	997	0.2	υ 1
9	A1	982	1.0	−13	0.56	983	0.9	970	1.5	976	1.6	υ 12
10	A1	614	1.6	−5	0.36	611	1.4	606	1.8	605	1.4	υ 6b
11	A2	968	0.0	−26	0.0	981	0.0	954	0.0	945d	/	υ 17a
12	A2	814	0.0	−20	0.0	838	0.0	818	0.0	816d	/	υ 10a
13	A2	400	0.0	−9	0.0	404	0.0	395	0.0	/	/	υ 16a
14	B1	995	0.1	−27	0.07	992	0.1	965	0.2	972	0.1	υ 17b
15	B1	893	0.5	−22	−0.11	910	0.4	888	0.3	874	0.9	υ 10b
16	B1	720	78.1	−15	−4.89	733	81.3	717	76.4	706	55.9	υ 11
17	B1	668	20.1	−14	−0.95	674	12.6	660	11.7	657	1.1	υ 4
18	B1	424	6.2	−8	0.16	430	5.4	422	5.6	416	3.4	υ 16b
19	B2	3182	17.1	−153	11.00	3202	13.6	3049	24.6	3071	10.6	υ 20b
20	B2	3166	4.5	−134	−1.25	3182	5.8	3048	4.5	3060	0.1	υ 7a
21	B2	1630	1.7	−34	−0.57	1663	2.0	1628	1.4	1624(1593c)	0.1	υ 8b
22	B2	1460	4.7	−28	0.25	1467	6.4	1439	6.7	1432	6.3	υ 3
23	B2	1334	0.3	−17	−0.11	1312	0.0	1294	0.2e	1321	0.3	υ 14
24	B2	1302	0.1	−24	0.03	1275	0.2	1251	0.2	1283	3.6	υ 9b
25	B2	1171	0.1	−12	0.01	1163	0.1	1151	0.1	1159	0.1	υ 15
26	B2	1069	3.8	−8	−0.17	1077	3.5	1070	3.3	1063	1.1	υ 18b
27	B2	594	0.6	−6	−0.04	593	0.6	587	0.6	587	0.2	υ 6a

^aExperimental data from Ref.³⁷

^bAssignment based on the Wilson notation¹¹⁶ proposed for the numbering of aromatic ring modes.

^cReassigned in Raman spectrum³⁸.

^dObserved only in the Raman spectrum³⁸.

^eAnharmonic IR intensity computed at the B3LYP/SNSD level.