Table 3. Computed Nature, Excitation Energies (ΔE, in eV), Oscillator Strengths (f), and Electric Dipole Moments (μ, in D) for the Lowest Electronic States in Phenylalanine.

state	nature	ΔECASPT2	f	μ
S0	85.8%...	...	...	4.85
S1	67.2% πr πr*	4.66 (4.64)27	0.000053	4.92
S2	71.6% nCOπCO*	5.62	0.00186	3.67
S3	78.3% πr πr*	5.67	0.00265	4.35
S4	80.4% πr πr*	6.12	0.784	4.64