Statistical mechanics of surface tension and Tolman length of dipolar fluids

The Tolman length (delta (infinity)) characterizes the first-order correction to the surface tension (sigma (infinity)) due to curvature of the interface. Statistical mechanical expressions for sigma (infinity) and delta (infinity) were derived previously by Blokhuis and Bedeaux [Physica A 1992, 184, 42] for nonpolar fluids. Here Blokhuis and Bedeaux's approach is extended to dipolar fluids. Two approximations to the pair correlation function are employed, and their effects on sigma (infinity) and delta (infinity) are examined. The dependence of sigma (infinity) and delta (infinity) on temperature and dipole moment is also explored. It is found that sigma (infinity) increases with the dipole moment while \ delta (infinity)\ decreases as the dipole moment is increased. The sign of delta (infinity) is, however, negative.