Developing a Multi-Phase Equation of State for Crystalline Polymorphs of Acetaminophen
Category: Research Poster
Author(s): Lucy Kelley
Presenter(s): Lucy Kelley
LA-UR-25-26549 Acetaminophen, most widely known as a pharmaceutical, is an organic molecular crystal with applications in shock physics as an inert mock for energetic materials. In this work we develop analytical equations of state for forms I, II, and highly metastable form III of acetaminophen, as well as a pressure-temperature phase diagram for forms I and II. Density Functional Theory (DFT) code CP2K is used to optimize the single unit cell geometries at zero temperature and pressures of 0-10 GPa as well as to calculate the cold curves for each polymorph. The cell geometries optimized by DFT are then used with Python package phonopy to develop the phonon density of states (DOS). This cold curve and DOS data is fitted to the MACAW reference curve to obtain EOS and thermodynamic parameters in addition to the Helmholtz and Gibbs free energy in order to predict the polymorphism and thermodynamic properties of acetaminophen at high pressure and high temperature.