Structures and stability of HPO3 isomers

The potential energy surface (PES) of HPO3 system including nine isomers and eleven transition states was predicted at B3LYP/6-311 + + G(3df, 3pd) level of theory, and the connections were checked by intrinsic reaction coordinate calculations. The calculated results indicated that in HPO3 system thermodynamically the most stable species HOPO2 with planar structure (E1), (cis, cis) -HOOPO conformational isomer (E3), and stereo HP(O)O-2 with C-s symmetry, were found to have higher kinetic stability. The predicted results are in good agreement with previous experimental studies. Two new stereoisomers with HOPO2 connectivity obtained in this work were unstable because of their very low dissociation energies.