Figure 8.

Electrostatic properties of the ground and first three excited singlet states of the equilibrium ground state (left; Franck-Condon) and S₁/ICT minimized (right) geometries of the peridinin model compound in methanol. The contours in the S₀ panels display the charge distribution in the ground state, with red representing regions of net positive charge and blue representing regions of net negative charge. The contours for S₁, S₂, and S₃ (upper three rows) show the charge shifts that accompany excitation into the respective excited states. Red contours now represent regions of increased positive charge and blue contours represent regions of increased negative charge after excitation. Properties are based on level-three SAC-CI methods, and the configuration interaction included 3606 singles and ∼890,000 doubles. The dipole-moment changes (δm) are relative to the ground-state dipole moment and are evaluated in terms of vector differences (see text). The oscillator strengths (f) are for electronic transitions from the ground state. The arrows show the directions, but not the magnitudes, of the dipole moments or dipole-moment changes. The character of the S₃ states differs for the two geometries (nπ^∗ for ground state geometry (left), ππ^∗ for S₁ minimized geometry (right)). The level ordering from the SAC-CI and EOM-CCSD (Fig. 6) is different (see Theoretical methods).