. 2020 Jul 27;60(8):3854–3863. doi: 10.1021/acs.jcim.0c00423

Table 2. Average Absorption Wavelength (λ, nm), Oscillator Strength (f), and Two-Photon Absorption Cross Section (σ^2PA, GM) for the Two Lowest Excitations for Three Fluorophores Computed Using the TD-DFT/MM and RI-CC/MM Levels of Theory.

System		Flu1	Flu2	Flu3
	B3LYP/TZVP
S₀ → S₁	λ	349	396	546
	f	0.269	0.258	0.157
	σ^2PA	31	193	154
S₀ → S₂	λ	332	370	431
	f	0.039	0.033	0.231
	σ^2PA	6	7	176
	CAM-B3LYP/TZVP
S₀ → S₁	λ	315	355	376
	f	0.205	0.288	0.353
	σ^2PA	16	176	227
S₀ → S₂	λ	306	293	337
	f	0.061	0.100	0.137
	σ^2PA	7	14	190
	CC2/TZVP
S₀ → S₁	λ	325	367	396
	f	0.165	1.175	0.789
	σ^2PA	30	507	541
S₀ → S₂	λ	313	305	347
	f	0.110	0.016	0.492
	σ^2PA	31	22	216
	Experiment
S₀ → S₁	λ	352	384	441
	σ^2PA	674	293	619

Table 2. Average Absorption Wavelength (λ, nm), Oscillator Strength (f), and Two-Photon Absorption Cross Section (σ2PA, GM) for the Two Lowest Excitations for Three Fluorophores Computed Using the TD-DFT/MM and RI-CC/MM Levels of Theory.