AB INITIO STUDY OF THE COMPRESSIBILITY AND ELECTRONIC PROPERTIES OF CRYSTALLINE PURINE

The structure and electronic properties of crystalline purine are studied by ab initio calculations based on the density functional theory with regard to the dispersion interaction depending on the pressure up to 1 GPa. Purine is shown to be characterized by a negative linear compressibility, and its mechanism is determined at the microscopic level. Elastic constants, linear compressibilities, and elastic moduli of purine are calculated. Based on the electron density topological analysis, the hydrogen bond between purine molecules is investigated. The band gap of purine is calculated and its change with pressure is predicted.