An application of the simple model of positronium-induced cavities to orthopositronium annihilation rates in ethane gas

Abstract

The authors have analysed the density and temperature dependences of orthopositronium annihilation rates in ethane gas following the simple model of positronium-induced cavities. The results obtained for the potential barrier, size of the cavity and positronium binding energy show that a bound state of positronium does not exist in this cavity. This is further supported by calculations presented for the changes in free energy due to positronium trapping following the self-consistent field model. An analysis of these annihilation rate data following a simple model of density fluctuations provides a reasonably good description of the observations for relatively small density fluctuations.