Table 5. Relative energies (eV) of Adiabatic, Diabatic, and Intermediate States in the Lowest Singlet Excited States of Tetracyanoethylene (TCNE)···Methyl Vinyl Ether and TCNE···Naphthalene Exciplex^a.

(X)···(Y)		(TCNE)···(MeOCH=CH2)		(TCNE)···(naphthalene)b
energy terms		[S0] geom	[S1] geom	[S0] geom	[S1] geom
hνabad	X*[EC]	4.68	4.41	4.58	4.44
	Y*[EC]	6.81	6.49	4.61, 4.69	4.65, 4.50
ΔEdist	X[EC]	0.00	0.17	0.02	0.22
	Y[EC]	–0.02	–0.03	–0.02	0.12
ELex	(X*•Y)	4.55	4.67	4.35	4.27
	(X•Y*)	6.60	7.04	4.40, 4.48	4.56, 4.42
EEx	(X•Y)+*	4.46	4.58	4.10	3.87
	(X•Y)-*	6.69	7.10	4.40, 4.69	4.56, 4.76
ESE	(X•Y)+SE	3.04 (CT), 4.42	1.90 (CT), 4.69	2.42 (CT)c	1.77 (CT)c
				3.16 (CT),c 4.12	2.81 (CT),c 3.98
				4.53 (CT)c	4.13 (CT)c
	(X•Y)-SE	6.65	7.10	4.41, 4.69	4.61, 4.81
E(XY)	(XY)1*	2.62 (CT), 4.29	1.19 (CT), 4.63	1.67 (CT)c	1.15 (CT)c
				2.46 (CT)c	2.29 (CT)c
				3.77 (CT)c	3.45 (CT)c
				4.32	4.12
	(XY)2*	NAd	NAd	4.40, 4.51	4.38, 4.53

^aAll energies are given relative to the adiabatic ground state energies of monomers. The M06-2X density functional and the cc-pVDZ basis set are used. The energy terms may be compared with the illustration of Scheme 1.

^bTwo close-lying states are given for naphthalene with L_b first followed by L_a.

^cCharge transfer (CT) states, respectively from HOMO, HOMO–1, and HOMO–2 of naphthalene to the LUMO of TCNE.

^dNot assigned.