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

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