The thermodynamical calculations of uranium-water vapor system

In this paper, we study the relative stable molecular structures of uranium-water vapor system. For the uranium atom were used the relativistic effective core potential and contracted valued basis sets (6s5p2d4f)/[3s3p2d2f], and for oxygen and hydrogen atoms were used 6-311G** basis sets. We obtain the electronic state, geometric structure, energy, harmonic frequency, mechanical property, etc. of these six quintuple relative stable structures. It indicated that the first step of uranium-water vapor reaction is the interaction of uranium and oxygen atoms. The thermodynamical stability of UOH2 (5 A,) was calculated and its disassociation Gibbs free energy DeltaG(o)decreased with increasing temperature The result showed that low temperature favoured its existence.