E0196

Predicting Crystalline Structures of Hydrogen-Bonded Organic Molecules. Donovan N. Chin, Moldyn Inc., G. Tayhas R. Palmore, U. California-Davis, George M. Whitesides, Harvard University

An efficient computational approach to predicting crystalline structures of hydrogen-bonded organic molecules will be presented. In general, the two problems with using computations to predict crystal structures are 1) the astronomical amount of possible molecular orientations that most be searched, 2) the inadequacy of the force fields to discern polymorphs within 1-2 kcal/mol. Our method directly tackles these problems in a very efficient way using the following two key components. First, a simulated annealing protocol that biases the generation of energetically favorable structures at a given temperature. Second, a screening protocol that restricts these energetically favorable structures to have `reasonable hydrogen-bonded' patterns. We will show that our computational method as applied to `molecular tapes' are useful strategies towards the goals of crystal engineering.