TABLE I.

The calculated electronic excitation energies (nm), corresponding oscillator strengths, and the corresponding compositions of the low-lying singlet excited states for HBT-FS, Compound 2, and Compound 3.

	Transition	λ (nm)	f a	Compositionb	CI (%)c
HBT-FS	S0→S1	392	0.6358	H→L	95.55%
	S0→S2	363	0.0066	H-1→L	98.48%
	S0→S3	345	0.2286	H-2→L	71.09%
	S0→S4	335	0.0111	H-3→L	73.23%
Compound 2	S0→S1	419	0.7075	H→L	96.42%
	S0→S2	359	0.0364	H-1→L	84.99%
	S0→S3	352	0.4659	H-2→L	81.57%
Compound 3	S0→S1	307	0.3983	H→L	68.62%

^aOscillator strength.

^bH, HOMO (highest occupied molecular orbital) and L, LUMO (lowest unoccupied molecular orbital).

^cCI, Composition index.