Spin-flip approach within time-dependent density functional tight-binding method: Theory and applications

Mayu Inamori, Takeshi Yoshikawa, Yasuhiro Ikabata, Yoshifumi Nishimura, Hiromi Nakai

Research output: Contribution to journalArticle

Abstract

A spin-flip time-dependent density functional tight-binding (SF-TDDFTB) method is developed that describes target states as spin-flipping excitation from a high-spin reference state obtained by the spin-restricted open shell treatment. Furthermore, the SF-TDDFTB formulation is extended to long-range correction (LC), denoted as SF-TDLCDFTB. The LC technique corrects the overdelocalization of electron density in systems such as charge-transfer systems, which is typically found in conventional DFTB calculations as well as density functional theory calculations using pure functionals. The numerical assessment of the SF-TDDFTB method shows smooth potential curves for the bond dissociation of hydrogen fluoride and the double-bond rotation of ethylene and the double-cone shape of H3 as the simplest degenerate systems. In addition, numerical assessments of SF-TDDFTB and SF-TDLCDFTB for 39 S0/S1 minimum energy conical intersection (MECI) structures are performed. The SF-TDDFTB and SF-TDLCDFTB methods drastically reduce the computational cost with accuracy for MECI structures compared with SF-TDDFT.

Original languageEnglish
Pages (from-to)1538-1548
Number of pages11
JournalJournal of Computational Chemistry
Volume41
Issue number16
DOIs
Publication statusPublished - 2020 Jun 15

Keywords

  • conical intersection
  • degenerate phenomena
  • long-range correction
  • spin-flip
  • time-dependent density functional tight-binding method

ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Mathematics

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