. Author manuscript; available in PMC: 2009 Oct 29.

Published in final edited form as: J Phys Chem A. 2009 Oct 29;113(43):11685–11692. doi: 10.1021/jp902754p

TABLE 1.

Calculated S₁ Vertical Excitation Energy (nm) of RH, HB, and MUV with PSBR and SBR at ONIOM-EE Geometries in the Gas Phase (QM-none) and in the Presence of Pigment Environments (QM/MM) with QM Model R1 and 6-31G* Basis Set^a

pigment (experiment)	retinal protonation	method	TD-B3LYP	SORCI+Q(6/6)^b	MRCISD+Q(6/6)^b
RH (500 nm)	PSBR	QM-none	560	616	626
		QM/MM	503	495	499
	SBR	QM-none	408	328	319
		QM/MM	429	336	324
HB (414 nm)	PSBR	QM-none	634	556	546
		QM/MM	488	424	448
	SBR	QM-none	382	304	295
		QM/MM	402	318	304
MUV (359 nm)	PSBR	QM-none	596	550	541
		QM/MM	469	430	447
	SBR	QM-none	396	328	322
		QM/MM	409	335	321

S₁ and S₂ vertical excitation energies of SBR are very close to each other. Only the absorbing state of SBR is given for relating the calculations with the experiments. The calculated oscillator strengths of the first absorbing state are 1.2–2.0 for both PSBR and SBR.

Estimated errors in SORCI+Q and MRCISD+Q vertical S₁ excitation energies with the present computational settings (see ref 7) are 15 nm red shift for PSBR and 50 nm blue shift for SBR.