pyVPT2: Interoperable software for anharmonic vibrational frequency calculations

Philip M Nelson; C David Sherrill

doi:10.1063/5.0251445

pyVPT2: Interoperable software for anharmonic vibrational frequency calculations

J Chem Phys. 2025 Jan 21;162(3):032501. doi: 10.1063/5.0251445.

Authors

Philip M Nelson¹, C David Sherrill¹

Affiliation

¹ Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, and School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.

PMID: 39820337
DOI: 10.1063/5.0251445

Abstract

We present pyVPT2, a program to perform second-order vibrational perturbation theory (VPT2) computations to obtain anharmonic vibrational frequencies. This program is written in Python and can utilize any of the several quantum chemistry programs that have been interfaced to the QCEngine project of the Molecular Sciences Software Institute (MolSSI). The requisite single point energy, gradient, or Hessian computations can be automatically performed in a distributed-parallel fashion by optionally using the MolSSI's QCFractal software. With pyVPT2, VPT2 anharmonic frequencies can now be computed using quantum chemistry programs that lack their own VPT2 capabilities.