Quantum chemical potential energy surfaces for HXeCl Original Research Article

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 RXeCl=267.4 pm and RXeH=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 RXeCl=249 pm and RXeH=267 pm. The depth of this minimum is 2.0 eV. The second triplet state shows a van der Waals minimum at RXeCl=320 pm and RXeH=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 νXeCl, 547 cm−1 for δ (doubly degenerate) and 1788 cm−1 for νXeH. The corresponding scaled frequency for νXeH agrees well with the experimental one.