Toward Building a Crystal Structure Prediction Framework

Purdue University, West Lafayette IN

Investigators

Abstract

TECHNICAL SUMMARY Crystal packing of organic molecules is poorly understood; predicting likely crystal structures of a given compound is even more challenging. This research project, supported by the Solid State and Materials Chemistry (SSMC) program of the Division of Materials Research (DMR), is to study how organic molecules interact in the solid state so as to learn and build up the fundamental understanding that will lead to viable solutions for crystal structure prediction. In particular, the locality of intermolecular interactions, both strength and directionality, in organic crystals will be investigated within the framework of conceptual density functional theory by utilizing such concepts as softness, Fukui function, and crystallization force. Through calculation and analysis of electronic structures of molecules and their respective crystal structures, the project will seek and establish the underlying, inherent linkage between a molecule's structure and its interacting characteristics with other molecules in crystals. The influence of a molecule's conformation on its intermolecular spatial arrangement is further studied by electronic calculations and crystallization experiments. Upon successful completion of this research project, a methodological framework will be built for advancing into practical tools to understand crystallization and to predict crystal structures of organic compounds. NON-TECHNICAL SUMMARY Fascination of organic crystals lies in the infinite periodicity and intriguing complexity in the three-dimensional structure that is interweaved by weak forces. Despite years of vigorous studies, the scientific efforts to predict crystal structures have proved to be primitive, powerless in most cases, and in the end, futile. This research project aims at bringing advanced computational methods into the field and developing novel approaches for predicting crystal structures that are built upon ingenious ways of analyzing electronic structures of molecules and crystals. Moreover, the research will shed light on fundamental mechanisms of crystal growth and offer insights for designing new materials including pharmaceuticals, fine chemicals, and nonlinear optical materials. The project will serve as an excellent educational platform for undergraduate and graduate students to master their problem-solving skills and become future leaders in the area of organic materials.