How to do TDDFT calculations in solvent?


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Hi Yavar,

We have the COSMO model in NWChem. The COSMO potential is included in the TDDFT calculation but we don’t include the reaction of the excited-state density of the molecule on the solvent or the fast response (or the non-equilibrium response). The calculation is only done with the slow component. Including the fast or non-equilibrium component (which corresponds to eps_inf ~2.0 for most solvents) is like doing a calculation in a non-polar solvent (epsilon_static ~2.0). Since non-polar solvents don’t affect the excitation energies much, it’s not a bad approximation to neglect it. The other argument to neglect it is the time scale. The electronic excitations are too fast for total solvent rearrangement to occur.

We do have the non-equilibrium response in our implementation plans but I am not sure if we will have it ready by the next release.

Best,
-Niri
niri.govind@pnl.gov