Joel's paper in J. Chem. Theory Comp. examines the size of QM region necessary for computing converged aqueous absorption spectra for solutes of varying polarity. We used large QM solvation regions (up to 400 QM water molecules) to study if nonpolar solutes required less QM solvent to converge excitation energies and oscillator strengths. Surprisingly, we found that the convergence of the excitation energies computed with the CIS method correlated with solute polarity, but those for the TDDFT method did not.
March 31, 2017