and substitute this for ∆P in Eq. (2.16). This defines attachment and detachment components of the relaxed density and recovers a particle/hole picture that includes includes orbital relaxation. Relaxation effects can be especially significant for states with CT character, as demonstrated in Fig. for the case of a donor-acceptor complex consisting of naphthalene and tetracyanoquinone. Unrelaxed particle and hole densities (on the left in Fig. ) suggest that the S 1 state of the complex has almost perfect CT character, with the excited electron localized on the acceptor (tetracyanoquinone) and the hole localized on the donor (naphthalene). A dipole moment change of ∆µ = 14.9 D upon excitation underscores this CT character. However, both of the relaxed densities (on the right in Fig. ) are delocalized over both monomers. The change in dipole moment (∆µ = 10.9 D) is substantially reduced although still quite large. Note that the excitation energy is precisely the same regardless of which densities are used to visualize the transition in question, as is the ground-state dipole moment of 1.3 D, however the excited-state dipole moment changes significantly when computed using the relaxed density matrix for the excited state.