Modeling environmental effects in two-photon circular dichroism calculations

Abstract

Accounting for solvent effects in theoretical predictions of spectroscopic properties may be of significant importance since a solvent -and on a more general basis any environment -may influence key spectroscopic parameters in nontrivial ways -especially in relation to calculation of non-linear optical properties. At the simplest level, solvent effects may be included into quantum chemistry calculations by use of a dielectric continuum approach, however, such a description may fail in addressing correctly environment anisotropies as well as specific interactions such as e.g. hydrogen bonding. On the other hand, discrete embedding methods allow for a more correct description of an environment since such methods keep the atomistic nature of the environment intact. In this paper, two-photon circular dichroism (TPCD) spectra will be calculated for two different biaryl derivatives introducing solvent effects by two different discrete embedding schemes, i.e. polarizable embedding based on induced dipoles (PE) or the fluctuating charge (FQ) model. While we find inclusion of solvent effects on this molecular property to be important, we conclude at the same time that the influence of the solvent on the TPCD rotatory strength is accounted for in an overall rather equivalent manner by either embedding methods.