Abstract Scope |
The entropy of fusion (melting) was studied for Ge, Si, Bi, Sn, Li, Zn and Pb. The entropy of fusion comes from atom vibrations, configurations, and electronic excitations. Inelastic neutron scattering and machine-learned molecular dynamic simulations were used to plot the vibrational entropy of fusion versus the total entropy from the latent heat. The plot showed that Richard’s rule, which states that melting occurs with an entropy of 1.2kB per atom, is correct when there is zero vibrational entropy of melting. Deviations from Richard’s rule are proportional to changes in vibrational entropy during melting plus an additional configurational entropy of ~80% of the vibrational entropy. For the potential energy landscape, this trend suggests a correlation between the change in the number of basins and the change in their inverse curvature during melting. Similar measurements on the melting of eutectic alloys are underway. Support by DOE BES Grant DE-FG02-03ER46055. |