Ne-HBr复合物CCSD(T)势能面对转动非弹性分波截面的影响

利用非线性最小二乘法拟合在CCSD(T)/aug-cc-pVQZ理论水平下计算的相互作用能，得到了基态Ne-HBr复合物势能面的解析表达式.在此基础上，采用量子密耦方法计算了入射能量分别为40，60，80 和100meV时，Ne原子与HBr分子碰撞的分波截面，详细讨论了CCSD(T)势能面的长程吸引和短程各向异性相互作用对非弹性分波截面的影响.结果表明：(1)总非弹性分波截面主要来自j=0 →j′=1, 2跃迁.高J端的尾部极大是势能面长程吸引阱的贡献，主要来自j=0 →j′=1跃迁；低J端的主极大是短程排斥的贡献，主要来自j=0 →j′=2跃迁；极小值是短程排斥和长程吸引作用相互抵消的结果.(2)尽管不同入射能量时非弹性分波截面的峰值和极小值对应的总角动量量子数J各不相同，但它们对应于几乎相同的碰撞参数，取样势能面的相同部分.

The influence of the CCSD (T) potential energy surface of the Ne-HBr complex on rotationally inelastic partial cross sections

An analytic expression of the potential energy surface (PES) of the ground state of the Ne-HBr complex has been obtained by utilizing nonlinear least square method to fit the intermolecular interaction energies, which have been calculated at the coupled cluster singles and doubles including the connected triple excitation level and with the augmented correlation consistent polarized quadruple zeta basis set (CCSD (T)/aug-cc-pVQZ). On the basis of the above result, the partial cross sections (PCS) at the energies of 40, 60, 80 and 100meV for collisions between Ne atoms and HBr molecules have been calculated by using the quantum close-coupling method. Then the influence of the long-range attractive and the short-range anisotropic interaction of the CCSD (T) potential energy surface on the inelastic PCS has been discussed in detail. The results show: (1) The transitions of j=0 →j′=1, 2 contribute to the total inelastic PCS predominantly. The long-range attractive well of the PES results in the tail maximum of the inelastic PCS at the position of the higher J, which mainly comes from the transition of j=0 →j′=1. While the short-range repulsion results in the main peak at the position of the lower J, which mainly comes from the transition of j=0 →j′=2. The balance between the short-range repulsive and long-range attractive interaction results in a pronounced minimum in the inelastic PCS. (2) There is the same collision parameter corresponding to the maximums and minimums of the inelastic PCS at different incident energies although the corresponding quantum number J of total angular momentum is different. The collision parameter samples the same part of the PES.