Lev D. Gelb of Washington University is funded by the Theoretical and Computational Chemistry Program to study fluid phase equilibria at extreme conditions using Monte Carlo simulations based on first-principles energy evaluations. This method is being applied to a survey of the high-temperature fluid phase behavior of elemental systems across the periodic table. Applications include liquid-liquid and liquid-vapor transitions in a variety of elements. The solubility of elements in liquid metals is also under consideration, with future extensions to molecular fluids and coupled chemical and phase equilibria. This work is having a broader impact in providing high-quality phase coexistence data for systems for which experimental data are inaccurate or unavailable. These data are valuable for scientific and engineering applications from materials processing to energy productions. The codes developed in this project will be freely available online. They provide a platform for any project involving large numbers of semi-independent electronic structure calculations. The PI integrates the results of his research in his teaching activities, and actively involves undergraduates into computational research and training.