Quantum chemical potential energy surfaces for HXeCl

Abstract

Relativistic pseudopotential calculations are reported for HXeCl at the CISD level. Potential energy surfaces for the singlet ground state and two excited singlet states are shown for the linear case. The two lowest triplet states are also shown. The potential energy curve for the bending motion is shown for the singlet ground state. The optimized ground state structure is linear, with R XeCl=267.4 pm and R XeH=175.8 pm. The depth of the minimum is 0.9 eV. This structure agrees favorably with the earlier reported nonrelativistic ab initio results. The second excited singlet state of the linear system also shows a minimum at R XeCl=249 pm and R XeH=267 pm. The depth of this minimum is 2.0 eV. The second triplet state shows a van der Waals minimum at R XeCl=320 pm and R XeH=360 pm with a depth of 0.02 eV. The harmonic fundamental frequencies for the ground state, calculated at the CISD level are 263 cm −1 for ν XeCl, 547 cm −1 for δ (doubly degenerate) and 1788 cm −1 for ν XeH. The corresponding scaled frequency for ν XeH agrees well with the experimental one.