Quantum chemical approach for positron annihilation spectra of atoms and molecules beyond plane-wave approximation

Yasuhiro Ikabata, Risa Aiba, Toru Iwanade, Hiroaki Nishizawa, Feng Wang, Hiromi Nakai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We report theoretical calculations of positron-electron annihilation spectra of noble gas atoms and small molecules using the nuclear orbital plus molecular orbital method. Instead of a nuclear wavefunction, the positronic wavefunction is obtained as the solution of the coupled Hartree-Fock or Kohn-Sham equation for a positron and the electrons. The molecular field is included in the positronic Fock operator, which allows an appropriate treatment of the positron-molecule repulsion. The present treatment succeeds in reproducing the Doppler shift, i.e., full width at half maximum (FWHM) of experimentally measured annihilation (γ-ray) spectra for molecules with a mean absolute error less than 10%. The numerical results indicate that the interpretation of the FWHM in terms of a specific molecular orbital is not appropriate.

Original languageEnglish
Article number184110
JournalJournal of Chemical Physics
Volume148
Issue number18
DOIs
Publication statusPublished - 2018 May 14

Fingerprint

Positron annihilation
Positrons
positron annihilation
plane waves
Molecular orbitals
Wave functions
Full width at half maximum
Atoms
Molecules
positrons
molecular orbitals
approximation
atoms
Noble Gases
molecules
Electrons
Doppler effect
rare gases
rays
operators

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Quantum chemical approach for positron annihilation spectra of atoms and molecules beyond plane-wave approximation. / Ikabata, Yasuhiro; Aiba, Risa; Iwanade, Toru; Nishizawa, Hiroaki; Wang, Feng; Nakai, Hiromi.

In: Journal of Chemical Physics, Vol. 148, No. 18, 184110, 14.05.2018.

Research output: Contribution to journalArticle

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