Many-Body Dispersion Interactions in Molecular Crystal Polymorphism

TL;DR

This paper demonstrates that incorporating many-body dispersion interactions beyond pairwise approximations is essential for accurately predicting and understanding polymorphism in molecular crystals, with glycine serving as a key benchmark.

Contribution

It introduces the importance of non-additive many-body dispersion energy in modeling molecular crystal polymorphism, improving predictive accuracy.

Findings

MBD energy significantly influences polymorph stability.

DFT+MBD accurately predicts glycine crystal polymorphs.

Many-body effects are crucial for qualitative and quantitative descriptions.

Abstract

Polymorphs in molecular crystals are often very close in energy, yet they may possess markedly different physical and chemical properties. The understanding and prediction of polymorphism is of paramount importance for a variety of applications, including pharmaceuticals, non-linear optics, and hydrogen storage. Here, we show that the non-additive many-body dispersion (MBD) energy beyond the standard pairwise approximation is crucial for the correct qualitative and quantitative description of polymorphism in molecular crystals. This is rationalized by the sensitive dependence of the MBD energy on the polymorph geometry and the ensuing dynamic electric fields inside molecular crystals. We use the glycine crystal as a fundamental and stringent benchmark case to demonstrate the accuracy of the DFT+MBD method.