@article{c92ed6b8c8fd4aeea5a19eadae0311b9,
title = "Quantum chemical approach for positron annihilation spectra of atoms and molecules beyond plane-wave approximation",
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.",
author = "Yasuhiro Ikabata and Risa Aiba and Toru Iwanade and Hiroaki Nishizawa and Feng Wang and Hiromi Nakai",
note = "Funding Information: Some of the present calculations were performed at the Research Center for Computational Science (RCCS), Okazaki Research Facilities, Institutes of Natural Sciences (NINS). This study was supported in part by a Grant-in-Aid for Scientific Research “KAKENHI No. 26248009” from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, and by the Core Research for Evolutional Science and Technology (CREST) Program, “Theoretical Design of Materials with Innovative Functions Based on Relativistic Electronic Theory” of the Japan Science and Technology Agency (JST). F.W. acknowledges the Australian Research Council (ARC) Discovery Project (DP) No. DP110101371. Publisher Copyright: {\textcopyright} 2018 Author(s).",
year = "2018",
month = may,
day = "14",
doi = "10.1063/1.5019805",
language = "English",
volume = "148",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "18",
}