. Author manuscript; available in PMC: 2014 Aug 1.

Published in final edited form as: Photochem Photobiol Sci. 2013 Aug;12(8):1328–1340. doi: 10.1039/c3pp25430e

Table 2.

Comparison of Methods: Vertical low-lying singlet excited state energies (ΔE) in eV and oscillator strength (f) of A-T base pair calculated with the CC2/TZVP and ωB97XD/6–31G* methods (ε = 1).

State	A-T base pair

	CC2/TZVP^a		ωB97XD /6–31G*^b
	Transition	ΔE	Transition	ΔE (f)
S1	T(n) → T(π*)	4.94	T(n) → T(π*)	5.33 (0.0001)
S2	T(π) → T(π*)	5.21	T(π) → T(π*)	5.41 (0.1777)
S3	A(π) → A(π*)	5.40	A(π) → A(π*)	5.51 (0.1132)
S4	A(π) → A(π*)	5.47	A(π) → A(π*)	5.57 (0.1947)
S5	A(n) → A(π*)	5.54	A(n) → A(π*)	5.63 (0.0003)
S6	-	-	A(n) → A(π*)	6.11 (0.0001)
S7	A(π) → T(π*)	6.04	A(π) → T(π*)	6.32 (0.0034)

Ref. 36.

Present calculation.