Repulsive interactions of deuterium and nitrogen under high pressures

High-pressure studies of simple diatomic mixtures are fundamental to understanding the nature of intermolecular interactions and, thereby, their physical and chemical transformations. In this paper, we present the Raman and x-ray studies of D$_{2}$:N$_{2}$ mixtures to 70 GPa. Our results indicate that the evolution of Raman spectra of D$_{2}$ under pressure is apparently coupled to the structural phase transitions in the host N$_{2}$ lattice and their crystal structures. A large blue-shift of D$_{2}$ vibron in N$_{2}$ lattice at high pressures indicates a highly repulsive nature of intermolecular interactions between the host N$_{2}$ and guest D$_{2}$ molecules. We will discuss about the origin of such repulsive interaction in terms of the crystal structure of the mixture at high pressures.