  The curvature dependence of the surface tension is related to the excess
equimolar radius of liquid drops, i.e., the deviation of the equimolar radius
from that defined with the macroscopic capillarity approximation. Based on the
Tolman [J. Chem. Phys. 17, 333 (1949)] approach and its interpretation by
Nijmeijer et al. [J. Chem. Phys. 96, 565 (1991)], the surface tension of
spherical interfaces is analysed in terms of the pressure difference due to
curvature. In the present study, the excess equimolar radius, which can be
obtained directly from the density profile, is used instead of the Tolman
length. Liquid drops of the truncated-shifted Lennard-Jones fluid are
investigated by molecular dynamics simulation in the canonical ensemble, with
equimolar radii ranging from 4 to 33 times the Lennard-Jones size parameter
sigma. In these simulations, the magnitudes of the excess equimolar radius and
the Tolman length are shown to be smaller than sigma/2. Other methodical
approaches, from which mutually contradicting findings have been reported, are
critically discussed, outlining possible sources of inaccuracy.
