The study of crystal polymorphism inevitably involves delicate questions related to the energetics of crystal packing. Simplistic approaches have not shown promise, whereas careful first principles based methods, involving more theory and less empiricism, have proved promising. Nonetheless, the treatment of long ranged interactions in crystal packing needs to be carefully addressed. This year we studied an important but poorly understood question of the correct pressure tensor in a large but finite crystal. Additionally we developed a novel and efficient method for Coulombic interactions in these systems, whether studied classically or quantum chemically. We are currently exploring speedups in these time consuming calculations.
