Potential Energy Surfaces and Dynamics of High Energy Materials

On the theoretical side, a new highly scalable code for frozen core second order perturbation theory gradients for closed shell molecules has been developed. The development of analogous codes for molecules with unpaired electrons is in progress. A working unrestricted second order perturbation theory code is now in GAMESS, and work on a scalable version of this code will begin shortly. The derivation for the spin-restricted open shell second order perturbation theory gradients has been completed. Other important developments are new convergence methods for MCSCF wavefunctions that facilitate MCSCF calculations on large molecules, the derivation of gradients for multi-reference second order perturbation theory, further developments of our effective fragment potential EFP method for studying solvation and liquid behavior, the development of molecular dynamics and Monte Carlo methods to facilitate the study of solvation and liquid behavior, the development and implementation of a new method for producing global potential energy surfaces from sets of ab initio points, the development and implementation of a gridless approach to density functional theory, and the development and implementation of a general, all electron MCSCF approach to spin-orbit coupling. With regard to applications, considerable progress has been made in our understanding of the mechanisms for formation of POSS polyhedral oligomeric silsesquioxanes reaction. Careful studies of the potential energy surfaces of B and B2 interacting with 112 have been carried out, and similar studies for Al have been initiated. The reactions leading to Al and B oxides when these species are burned in a rocket engine are underway. Several studies of high energy organic and inorganic compounds are ongoing.