Prediction of the Unknown Crystal Structure of Creatine Using Fully Quantum Mechanical Methods

Presented in this study is the full ab initio prediction of a previously unknown organic crystal structure. For the accurate prediction of crystal structures, the weak intermolecular forces must be well-represented. Solid-state density functional theory corrected for dispersion forces (DFT-D) is perhaps the most effective method for providing accurate descriptions of such forces in periodic systems. The success of DFT-D in crystal structure prediction is demonstrated in the prediction of the crystal structure of creatine, which has never been experimentally determined. The proposed P21/c structure was unquestionably verified by powder X-ray diffraction and terahertz spectroscopy, demonstrating a high degree of accuracy for the predicted structure. This clearly demonstrates the capacity and the feasibility of using full quantum mechanical methods in crystal structure prediction.