Donor excitation response function

Kobko et al.200 have used a third order response function formalism with TDHF and TDDFT to assess different levels of theory for calculations of excited state structure and nonlinear optical responses in donor-donor and donor-acceptor Ji-conjugated molecules. They make suggestions for numerically efficient approximations. 

Bartkowiak reviewed the connection between the NLO response and solva-tochromlc behavior of donor-acceptor Tr-conjugated molecules. The marked NLO properties of these molecules are associated with an intra-molecular charge-transfer excited state. This author points out that the environmental interactions may have a very significant effect on the hyperpolarizabilities (they may even lead to a change of sign). Bartkowiak shows that a simple two-state model combined with the solvatochromic methods may allow the prediction of changes of in molecular hyperpolarizabilities as a function of the solvent polarity. 

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