Table 3. Excitation Energies of Adiabatic, Diabatic, and Intermediate States in the Lowest Singlet and Triplet Excited States Associated with the Acetone Dimeric and Acetone-Methyl Vinyl Ether (MVE) Exciplex Complexes^a.

(X)···(Y)		(Me2C=O)···(Me2C=O)		(Me2C=O)···(MVE)
energy terms		singlet	triplet	singlet	triplet
hνad	X*[EC]	3.80	3.53	3.79	3.53
	Y*[EC]	4.39	4.08	6.80	4.39
ΔEdist	X[EC]	0.75	0.75	0.82	0.82
	Y[EC]	–0.02	–0.02	–0.01	–0.01
ELex	(X*•Y)	3.58	3.31	3.64	3.38
	(X•Y*)	4.97	4.67	7.46	5.04
EEx	(X•Y)+*	3.58	3.31	3.64	3.38
	(X•Y)−*	4.97	4.67	7.34	5.04
ESE	(X•Y)+SE	3.52	3.26	3.64	3.38
	(X•Y)−SE	4.85	4.55	6.31 (CT),b 7.38	5.04
E(XY)	(XY)1*	3.53	3.22	3.63	3.39
	(XY)2*	4.66	4.46	5.76 (CT),b 7.27	4.51

^aAll energies are given in electron volts (eV), relative to the ground state energies of a monomer, X[S₀] and Y[S₀], or two separate molecules at their optimized structures, i.e., adiabatic ground-state energies are set equal to zero. Square brackets indicate optimized geometry used in energy calculations with S₀ for the ground state and EC as exciplex complex. All calculations for bimolecular complexes adopt the [EC] structure. The M06-2X density functional and the cc-pVTZ basis set are used in NOSI calculations. The energies terms may be compared with the illustration of Scheme 1.

^bCharge transfer (CT) state.