Basis Set Dependence of Optical Rotation Calculations with Different Choices of Gauge

Abstract

In this work, the basis set dependence of optical rotation (OR) calculations is examined for various choices of gauge/level of theory. The OR is calculated for a set of 50 molecules using B3LYP and CAM-B3LYP, and 17 molecules using coupled cluster with single and double ex- citations (CCSD). The calculations employ the correlation-consistent basis sets, aug-cc-pVζZ with ζ = D, T, Q. An inverse-power extrapolation formula is then utilized to obtain OR values at the complete basis set (CBS) limit. We investigate the basis set convergence for these methods and three choices of gauge: length gauge (with gauge-including atomic orbitals, LG(GIAOs), for DFT), the origin-invariant length gauge [LG(OI)], and the modified velocity gauge (MVG). The results show that all methods converge smoothly to the CBS limit and that the LG(OI) approach has a slightly faster convergence rate than the other choices of gauge. While the DFT methods reach gauge invariance at the CBS limit, CCSD does not. The significant difference between the MVG and LG(OI) results at the CBS limit, 26%, indicates that CCSD is not quite at convergence in the description of electron correlation for this property. On the other hand, gauge invariance at the CBS limit for DFT does not lead to the same OR values for the two density functionals, which is also due to electron correlation incompleteness. A limited comparison to gas-phase experimental OR values for the DFT methods shows that CAM-B3LYP seems more accurate than B3LYP. Overall, this study shows that the LG(OI) approach with the aug-cc-pVTZ basis set for DFT, and with the CBS(DT) extrapolation for CCSD, provides a good cost/accuracy balance.

Benchmarking Gaussian Basis Sets in Quantum-Chemical Calculations of Photoabsorption Spectra of Light Atomic Clusters

“…They reported that the [4s3p2d/3s] basis set also provides similar results as aug-cc-pVDZ basis set for the calculations of (hyper)polarizability. Parsons et al 25 have explored the basis set dependence of optical rotation calculations of various types of gauges. They found that the origin-invariant length gauge (LG-OI) gauge with aug-cc-pVTZ basis set provides a balance of cost and accuracy for DFT method.…”

Benchmarking Gaussian Basis Sets in Quantum-Chemical Calculations of Photoabsorption Spectra of Light Atomic Clusters

“…They reported that the [4s3p2d/3s] basis set also provides similar results as the augcc-pVDZ basis set for the calculations of (hyper)polarizability. Parsons et al 25 have explored the basis set dependence of optical rotation calculations of various types of gauges. They found that the origin-invariant length gauge (LG-OI) gauge with an aug-cc-pVTZ basis set provides a balance of cost and accuracy for the DFT method.…”