Wetting and melting behavior of oxygen films on graphite

Abstract

We report an ellipsometric coverage-vapor pressure isotherm study of multilayer oxygen films on graphite. Solid \ensuremath{\beta} oxygen is found to wet graphite at least from 37 to 43.8 K. The film thickness at melting is limited to four layers by intrusion of the nonwetting \ensuremath{\gamma} solid. Melting, except of the top layer, occurs in a single first-order transition, while there is evidence that the top layer of three-or-more-layer films melts continuously near 41 K.