4th International Workshop on Positron and Positronium Chemistry

J. Phys. IV France 03 (1993) C4-17-C4-27
DOI: 10.1051/jp4:1993402

Positron reactions with SF₆ in hexane studied by measurements of the Doppler broadening of the annihilation line

O.E. MOGENSEN and T. HIRADE

Chemistry Department, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki-ken 319-11, Japan

Abstract
The Doppler broadening (DB) of annihilation radiation spectra were measured for solutions of SF₆ in hexane at SF₆ concentrations up to 1 M. By use of a new program GAUSSFIT the DB-spectra were analyzed in terms of a sum of the resolution-convoluted angular correlation spectrum for hexane and one or more extra, gaussians. Positron annihilation with electrons bound in fluorine gives an unusually broad DB-component. This effect was used to show that the positron reacts with SF₆ in hexane with a rate constant of 2.3x10¹⁰ M^-1s^-1. The result agrees with previous predictions based on positronium yield results and the spur model of Ps formation.

© EDP Sciences 1993