Annihilation rates of ortho—positronium in organic liquids: correlation with liquid compressibility and polarization ratio |
| |
Authors: | GORDON R FREEMAN NORMAN H Mar |
| |
Institution: | Department of Chemistry , University of Alberta , Edmonton, T6G 2G2, Canada |
| |
Abstract: | The bubble model of ortho—positronium annihilation rates customarily employs the value of the planar-surface tension in the estimation of the (surface) energy required to expand a normal interstitial cavity to form the bubble. However, bubble radii are estimated to be only about 0.4 nm; the surface of such a small bubble is expected to have a tension different from that of the planar surface. We have replaced the surface tension parameter by the isothermal compressibility, which is thought not to have a nanostructure limitation. The model has been further improved by introducing the polarization ratio (n 2 D ? 1)/(n 2 D + 2) as a parameter, n D being the refractive index of the organic liquid. Calculations are presented for 20 liquids. |
| |
Keywords: | |
|
|