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pyVPT2: Interoperable software for anharmonic vibrational frequency calculations.

Philip M Nelson1, C David Sherrill1

  • 1Center 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.

The Journal of Chemical Physics
|January 17, 2025
PubMed
Summary
This summary is machine-generated.

We present pyVPT2, a new Python program for calculating anharmonic vibrational frequencies using second-order vibrational perturbation theory (VPT2). This tool enhances computational chemistry by enabling VPT2 on quantum chemistry programs that previously lacked this capability.

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Area of Science:

  • Computational chemistry
  • Quantum chemistry
  • Molecular modeling

Background:

  • Anharmonic vibrational frequencies provide crucial insights into molecular dynamics and spectroscopy.
  • Second-order vibrational perturbation theory (VPT2) is a standard method for calculating these frequencies.
  • Existing quantum chemistry software may lack built-in VPT2 capabilities, limiting accessibility.

Purpose of the Study:

  • To introduce pyVPT2, a Python program designed to compute anharmonic vibrational frequencies using VPT2.
  • To enable the use of VPT2 calculations with quantum chemistry programs that do not natively support it.
  • To streamline the process of obtaining anharmonic frequencies through automated computations.

Main Methods:

  • Development of pyVPT2 as a Python-based computational tool.
  • Integration with QCEngine and MolSSI's QCFractal for quantum chemistry program interfacing and distributed-parallel computations.
  • Automated execution of single point energy, gradient, and Hessian calculations.

Main Results:

  • Successful implementation of pyVPT2 for VPT2 anharmonic frequency computations.
  • Demonstrated ability to utilize various quantum chemistry programs interfaced with QCEngine.
  • Facilitated distributed-parallel execution of necessary computational steps.

Conclusions:

  • pyVPT2 expands the accessibility of VPT2 anharmonic frequency calculations.
  • The program enhances the utility of quantum chemistry software by adding VPT2 capabilities.
  • This work advances computational spectroscopy by providing a flexible and automated tool.