Abstract: Based on the relativistic effective core potential (RECP) for Pu atom and 6-311G* basis sets for H atom, the thermodynamic functions for PuH2(g) have been calculated by ab initio method, and the thermodynamic functions formed for PuH2(g)molecules have been worked out by thermodynamic method. The results of calculation show that PuH2(g) molecules are not thermodynamic stable.

Key words: PuH₂, Thermodynamic stability, Density functional theory(DFT)