Table 1. Vertical Excitation Energies in eV of the Singlet and Triplet States of Nitrobenzene (C_2v, MS-CASPT2).^a,b.

state	ΔE	fOSCc	configurationd	We	ΔQf
21A1	5.11	2.94–01	[π3(bz)]1[π*(NO2)]1	72	–0.32
31A1	7.60	1.06–02	[π1(bz)]1[π*(NO2)]1	33	–0.21
			[π3(bz)]0[π*(NO2)]2	15
11A2	3.83	<1.0–05	[nσ]1[π*(NO2)]1	68	+0.14
21A2	7.00	<1.0–05	[nσ]1[π3(bz)]1[π*(NO2)]2	27	+0.18
			[nσ]1[π3*(bz)]1	32
31A2	7.36	<1.0–05	[σ1(NO2)]1[σ2*(NO2)]1	55	+0.35
11B2	4.30	1.01–04	[σ1(NO2)]1[π*(NO2)]1	66	+0.08
21B2	7.02	1.13–05	[nσ]1[π2*(bz)]1	49	+0.29
			[nσ]1[π2(bz)]1[π*(NO2)]2	17
31B2	7.51	3.59–04	[σ1(NO2)]1[π3(bz)]1[π*(NO2)]2	21	+0.16
			[σ1(NO2)]1[π3*(bz)]1	37
11B1	4.72	4.83–03	[π3(bz)]1[π2*(bz)]1	20	–0.06
			[π2(bz)]1[π*(NO2)]1	45
21B1	5.81	3.97–02	[nπ]1[π*(NO2)]1	47	+0.15
			[nπ]1[π3(bz)]1[π*(NO2)]2	12
31B1	7.04	8.03–02	[π3(bz)]1[π2*(bz)]1	17	–0.18
13A1	4.03		[π3(bz)]1[π*(NO2)]1	61	–0.03
			[π2(bz)]1[π2*(bz)]1	16
23A1	4.75		[π2(bz)]1[π2*(bz)]1	59	–0.02
			[π3(bz)]1[π*(NO2)]1	15
33A1	6.88		[π1(bz)]1[π*(NO2)]1	37	–0.06
			[π1(bz)]1[π1*(bz)]1	23
13A2	3.63		[nσ]1[π*(NO2)]1	73	+0.12
13B2	4.18		[σ1(NO2)]1[π*(NO2)]1	67	+0.08
13B1	3.53		[nπ]1[π*(NO2)]1	59	+0.12
23B1	4.57		[π2(bz)]1[π*(NO2)]1	29	–0.05
			[π3(bz)]1[π2*(bz)]1	23
33B1	6.03		[π3(bz)]1[π2*(bz)]1	42	–0.11
			[π2(bz)]1[π*(NO2)]1	22

^aC_2v MP2/def2-TZVPP optimized geometry.

^bSA3-CASSCF reference wave function, IPEA = 0.25. Imaginary shift = 0.1.

^cOscillator strength.

^dMS-CASPT2 main electronic configurations of the excited states referred to the ground state configuration.

^eWeight of the configuration in %. Only contributions greater than 15% are included.

^fExcess of charge on the nitro moiety with respect to the ground state.