Positron-Electron Annihilation Process in (2,2)-Difluoropropane Molecule

Abstract

The positron-electron annihilation process in (2,2)-difluoropropane molecule and the corresponding gamma-ray spectra are studied by quantum chemistry method. The positrophilic electrons in (2,2)-difluoropropane molecule are found for the first time. The theoretical predictions show that the outermost 2s electrons of fluoride atoms play an important role in positron-electron annihilation process of (2,2)-difiuoropropane. In the present scheme, the correlation coefficient between the theoretical gamma-ray spectra and the experiments can be 99%. The present study gives an alternative annihilation model for positron-electron pair in larger molecules.

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

“…Conversely, the valence MOs have small FWHMs and large contributions. Here, we mention the lowest occupied valence orbitals (LOVO), which have attracted attention in previous PWP studies [25][26][27][28][29]31 because of the agreement with the FWHM of the experimental spectra. FWHMs.…”

“…5,6,[9][10][11][12][13][14][15][16][17] In addition, the annihilation spectra of molecules and noble gas atoms have been analyzed using the plane-wave positron (PWP) method. [18][19][20][21][22][23][24][25][26][27][28][29][30] The PWP method approximates the positronic wavefunction as a plane wave, while the electronic state is determined by a quantum chemical calculation. However, the PWP method severely overestimates a) Author to whom correspondence should be addressed: nakai@waseda.jp.…”