Comparison of absorption wavelength maximum (λ_{abs max}), fluorescence wavelength maximum (λ_{em max}), extinction coefficient, oscillator strength (f), S₀–S₁ transition state energy (ΔE, eV), transient dipole moment between ground and excited states (r_g), change of excited state dipole moment (Δμ), optical band gap (ΔE), first hyperpolarizability (β) of ethenyl indoles 1–9 in methanol^a.

	λ abs max (nm)	λ em max (nm)	(ε) (M−1 cm−1)	f	S0–S1 (ΔE) (eV)	(rg) debye	(Δμ) debye	(μe) debye	(β) (in 10−30) esu−1 cm5
1	413	590	23 900	0.69	2.50	7.79	9.86	18.25	115
2	335	395	18 800	0.57	3.34	6.37	5.52	9.51	20
3	327	396	10 800	0.34	3.41	4.86	5.19	7.76	9
4	327	404	17 800	0.58	3.40	6.35	5.77	6.82	17
5	322	390	24 400	0.81	3.40	7.45	6.29	7.66	24
6	324	405	12 200	0.44	3.34	5.51	4.18	6.62	9
7	418	558	22 823	0.61	2.47	7.36	9.44	18.38	106
8	374	563	11 464	0.32	2.83	5.03	14.21	18.55	43
9	370	588	20 000	0.56	2.87	6.64	17.78	27.10	90

^aOnsagar cavity radius “a” (in Å); 1: 4.53; 2: 4.47; 3: 4.38; 4: 4.55; 5: 4.43; 6: 4.45; 7: 4.74; 8: 4.75; 9: 5.12; ground state dipole moment μ_g (in debye): 1: 8.39; 2: 3.99; 3: 2.57; 4: 1.05; 5: 1.37; 6: 2.44; 7: 8.94; 8: 4.34; 9: 9.32; excited state dipole moment μ_e = Δμ^{(McRay method)} + μ^(TDDFT)_g.