The iterative procedure required to solve the statespecific eigenvalue problem in Eq. ( ) is relatively straightforward if there are no quasi-degeneracies, although this equation must be solved separately for each electronic state of interest. However, the presence of near-degeneracies may lead to convergence problems associated with root-flipping, and furthermore properties other than the energy (including oscillator strengths) are not entirely well-defined because the excited states are not eigenfunctions of a common Hamiltonian and are therefore not orthogonal to one another. To circumvent these difficulties, we next describe a perturbative approach to state-specific solvation, which furthermore allows for all of the solvent-corrected excitation energies to be obtained from a single calculation, including nonequilibrium corrections.