On the Performance of a Size-Extensive Variant of Equation-of-Motion Coupled Cluster Theory for Optical Rotation in Chiral Molecules

Abstract

The modified equation-of-motion coupled cluster approach of Sekino and Bartlett is extended to computations of the mixed electric-dipole/magnetic-dipole polarizability tensor associated with optical rotation in chiral systems. The approach – referred to here as a linearized equation-of-motion coupled cluster (EOM-CCL) method – is a compromise between the standard EOM method and its linear response counterpart, which avoids the evaluation of computationally expensive terms that are quadratic in the field-perturbed wave functions, but still yields properties that are size-extensive/intensive. Benchmark computations on five representative chiral molecules, including (P)-hydrogen peroxide, (S)-methyloxirane, (S)-2-chloropropionitrile, (R)-epichlorohydrin, and (1S,4S)-norbornenone, demonstrate typically small deviations between the EOM-CCL results and those from coupled cluster linear response theory, and no variation in the signs of the predicted rotations. In addition, the EOM-CCL approach is found to reduce the overall computing time for multi-wavelength-specific rotation computations by up to 34%.