Simulation of Vibrational Circular Dichroism Spectra Using Second-Order M{\o}ller-Plesset Perturbation Theory and Configuration Interaction Doubles

TL;DR

This study demonstrates the first wave-function-based calculations of atomic axial tensors using MP2 and CID methods, revealing significant electron correlation effects on vibrational circular dichroism spectra.

Contribution

It introduces a novel implementation for calculating atomic axial tensors with dynamic electron correlation effects using MP2 and CID methods.

Findings

Deviations of AATs from Hartree-Fock up to 49% depending on basis set.

Electron correlation significantly affects rotatory strengths in VCD spectra.

Maximum deviations of 62% and 49% in rotatory strengths for MP2 and CID with large basis sets.

Abstract

We present the first single-reference calculations of the atomic axial tensors (AATs) using wave-function-based methods including dynamic electron correlation effects using second-order M{\o}ller-Plesset perturbation theory (MP2) and configuration interaction doubles (CID). Our implementation involves computing the overlap of numerical derivatives of the correlated wave functions with respect to both nuclear displacement coordinates and the external magnetic field. Out test set included three small molecules, including the axially chiral hydrogen molecule dimer and (P)-hydrogen peroxide, and the achiral H2O. For our molecular test set, we observed deviations of the AATs for MP2 and CID from that of the Hartree-Fock (HF) method upwards of 49%, varying with the choice of basis set. For (P)-hydrogen peroxide, electron correlation effects on the VCD rotatory strengths and corresponding spectra were particularly significant, with maximum deviations of the rotatory strengths of 62% and 49% for MP2 and CID, respectively, using our largest basis set. The inclusion of dynamic electron correlation to the computation of the AATs can have a significant impact on the resulting rotatory strengths and VCD spectra.