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Distance Matrix based Crystal Structure Prediction using Evolutionary Algorithms

Crystal structure prediction (CSP) for inorganic materials is one of the central and most challenging problems in materials science and computational chemistry. This problem can be formulated as a global optimization problem in which global search algorithms such as genetic algorithms (GA) and particle swarm optimization have been combined with first principle free energy calculations to predict crystal structures given only a material composition or only a chemical system. These DFT based ab initio CSP algorithms are computationally demanding and can only be used to predict crystal structures of relatively small systems. The vast coordinate space plus the expensive DFT free energy calculations limits their efficiency and effectiveness. On the other hand, a similar structure prediction problem has been intensively investigated in parallel in the protein structure prediction community of bioinformatics, in which the dominating predictors are knowledge based approaches including homology modeling and threading that exploit known protein structures. Herein we explore whether known geometric constraints such as the pairwise atomic distances of a target crystal material can help predict/reconstruct its structure given its space group and lattice information. We propose DMCrystal, a genetic algorithm based crystal structure reconstruction algorithm based on predicted atomic pairwise distances. Based on extensive experiments, we show that the predicted distance matrix can dramatically help to reconstruct the crystal structure and usually achieves much better performance than CMCrystal, an atomic contact map based crystal structure prediction algorithm. This implies that knowledge of atomic interaction information learned from existing materials can be used to significantly improve the crystal structure prediction in terms of both speed and quality.