An investigation on the structural transition and stability of some actinide nitrides under pressure

•The present study gives the improved results after the inclusion of covalency in TBI effect for actinides.•It predicts the phase transition pressure, volume discontinuity and elastic properties at high pressure.•The inclusion of vander Waal effect is important as it is difficult in DFT and other ab intio calculations.•To explain the stability of the materials the Every’s and Blackman’s diagrams are analyzed.•The newly obtained values can consider as a future reference to the experimentalists.

A theoretical study of the structural and related properties of some actinide nitrides under high pressure has been carried out using three-body interaction (TBI) potential model. The present TBI model constitutes the long range Coulombic, three body interaction forces with inclusion of covalency effect, van der Waals’ interaction and short range overlap repulsive forces operative up-to next nearest neighbor ions. The covalency effect is introduced to explain the partial covalent nature of the present compounds. Using this static simulation technique we have investigated the phase transition pressures, volume collapses and elastic behaviour of ThN, NpN and CmN at high-pressures. A detailed discussion of stability criteria using various theories has also been done. The results found are well agreed with available experimental and other data.