8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P7.92Thu 811:10-14:00The surface free energy of a quasi-spherical dropletSanti Prestipino, 1 Alessandro Laio, 1 and Erio Tosatti 21 University of Messina, Contrada Papardo, 98166, Messina, Italy2 SISSA and CNR / INFM Democritos, Trieste, ItalyCentral to the theory of nucleation is the concept of a critical cluster, i. e. a droplet of the nucleatingphase that is in unstable equilibrium with the metastable matrix. Classical nucleation theory (CNT)treats the critical cluster as spherical, moreover assuming its surface free energy to be the same asfor the planar interface. We present a statistical field theory of the nucleating droplet that goesbeyond CNT in two respects: 1) small deviations of the cluster shape from sphericity are allowedand 2) spontaneous-curvature and bending-energy terms in the Hamiltonian are also kept intoaccount. With this theory, we evaluate the finite-size corrections to the surface free energy and findthat the Tolman correction is generally non-zero and temperature-dependent. We also compute thefree-energy landscape as a function of the volume and the surface area of the cluster, thus obtaininga measure of the deviations of the cluster shape from sphericity as a function of the cluster size.Finally, we analyse the nucleation barrier of the three-dimensional Ising model through the lensesof the theory so as to get a clue about the dependence of the surface tension and the Tolman lengthon the supersaturation in a typical case.92