Addressing an instability in unrestricted density functional theory direct dynamics simulations

Abstract

In Density Functional Theory (DFT) direct dynamics simulations with Unrestricted Hartree Fock (UHF) theory, triplet instability often emerges when numerically integrating a classical trajectory. A broken symmetry initial guess for the wave function is often used to obtain the unrestricted DFT potential energy surface (PES), but this is found to be often insufficient for direct dynamics simulations. An algorithm is described for obtaining smooth transitions between the open‐shell and the closed‐shell regions of the unrestricted PES, and thus stable trajectories, for direct dynamics simulations of dioxetane and its •OCH2‐CH2O• singlet diradical. © 2018 Wiley Periodicals, Inc.

Document Details

Document Type
Pub Defense Publication
Publication Date
Oct 26, 2018
Source ID
10.1002/jcc.25604

Entities

People

  • Shreyas Malpathak
  • William L Hase
  • Xinyou Ma

Organizations

  • Air Force Office of Scientific Research
  • Indian Institutes of Science Education and Research
  • National Science Foundation
  • Robert A. Welch Foundation
  • Texas Tech University

Tags

Fields of Study

  • Physics

Readers

  • Control Systems Engineering.
  • Quantum Chemistry
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.