Potential energy surface and quantum dynamics study of rovibrational states for HO3 (X2 A")

An analytic potential energy surface has been constructed by fitting to about 28 thousand energy points for the electronic ground-state (X-2 A '') of HO3. The energy points are calculated using a hybrid density functional HCTH and a large basis set aug-cc-pVTZ, i.e., a HCTH/aug-cc-pVTZ density functional theory (DFT) method. The DFT calculations show that the trans-HO3 isomer is the global minimum with a potential well depth of 9.94 kcal mol(-1) with respect to the OH + O-2 asymptote. The equilibrium geometry of the cis-HO3 conformer is located 1.08 kcal mol(-1) above that of the trans-HO3 one with an isomerization barrier of 2.41 kcal mol(-1) from trans- to cis-HO3. By using this surface, a rigorous qu'antum dynamics (QD) study has been carried out for computing the rovibrational energy levels of HO3. The calculated results determine a dissociation energy of 6.15 kcal mol(-1), which is in excellent agreement with the experimental value of Lester et al.