Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Materials Science and Engineering

Major Professor

David J. Keffer

Committee Members

Don M. Nicholson, Haikuan Xu, Orlando Rios


Techniques such as classical molecular dynamics [MD] simulation provide ready access to the thermodynamic data of model material systems. However, the calculation of the Helmholtz and Gibbs free energies remains a difficult task due to the tedious nature of extracting accurate values of the excess entropy from MD simulation data. Thermodynamic integration, a common technique for the calculation of entropy requires numerous simulations across a range of temperatures. Alternative approaches to the direct calculation of entropy based on functionals of pair correlation functions [PCF] have been developed over the years. This work builds upon the functional approach tradition by extending the recently developed entropy pair functional theory [EPFT] to three new material systems. Direct calculations of entropy for the BCC iron and FCC copper (modeled with the modified embedded atom method [MEAM] potential) and the Diamond Cubic silicon system (modeled with the Tersoff potential) are compared against a target entropy as determined by thermodynamic integration. The sources of and correction to the high temperature error in several proposed functional approaches is explored in depth. Finally, a working code is provided to the community via Github to implement the extended EFPT to compute entropy using trajectory files generated from a single simulation.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."