D_2在Ni(100)表面离解吸附的量子动力学研究

Quantum Dynamics of Dissociative Adsorption for D 2 on Ni(100) Surface

用量子含时波包法研究了Ｄ２在镍表面顶－桥位上离解吸附量子动力学．计算了不同入射动能及初始振转态的离解几率．讨论了分子的同核对称性、转动取向和振动激发对离解几率的影响，并与其他理论计算结果做了比较．

A time-dependent quantum wave packet method was used to study the dynamics of the dissociative adsorption of D 2 over the atop-to-bridge site on Ni(100) surface. A modified London-Erying-Polanyi-Sato(LEPS) potential energy surface with parameters chosen to represent the D 2/Ni(100) system has been used in present study. The three-dimensional(3D) dissociation probability of D 2 for different initial rotational and vibrational state as a function of the incident kinetic energy was calculated. The results show that the activated adsorption of a homonuclear D 2 at a fixed site with high rotation symmetry is forbidden at low energies if initial rotational states satisfy the symmetry condition j+m=odd due to the selection rule. There is a strong dependence of dissociation probability on the initial rotational projection quantum number m of the molecule at low energies. The rotational states (jj), which describes the in-plane rotation, is more higher favored for dissociation than the state (j0), which describes the out-of-plane rotation. The vibrational excitation increases the dissociation probability of D 2. It may be attributed to greater spatial extension of the vibrationally excited states (v>0) over the ground state (v=0). It is also fond that vibrational energy is more effective than translational energy in overcoming the barrier.