Xie Zhen, Braams Bastiaan J, Bowman Joel M
Cherry L. Emerson Center of Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
J Chem Phys. 2005 Jun 8;122(22):224307. doi: 10.1063/1.1927529.
An accurate global potential-energy surface (PES) is reported for H5(+) based on more than 100,000 CCSD(T)/aug-cc-pVTZ ab initio energies. This PES has full permutational symmetry with respect to interchange of H atoms and dissociates to H3(+) and H2. Ten known stationary points of H5(+) are characterized and compared to previous ab initio calculations. Quantum diffusion Monte Carlo calculations are performed on the PES to obtain the zero-point energy of H5(+) and the anharmonic dissociation energy (D0) of H5(+) --> H3(+) + H2. The rigorous zero-point state of H4D+ is also calculated and discussed within the context of a strictly classical approach to obtain the branching ratio of the reaction H4D+ --> H3(+) + HD and H2D+ + H2. Such an approach is taken using the PES and critiqued based on the properties of the quantum zero-point state. Finally, a simple procedure for adding the long range-interaction energy is described.
基于超过100,000个CCSD(T)/aug-cc-pVTZ从头算能量，报道了H5(+)精确的全局势能面（PES）。该PES在氢原子交换方面具有完全的置换对称性，并解离为H3(+)和H2。对H5(+)的十个已知驻点进行了表征，并与之前的从头算计算进行了比较。在该PES上进行了量子扩散蒙特卡罗计算，以获得H5(+)的零点能和H5(+)→H3(+) + H2的非谐解离能（D0）。在严格的经典方法框架内，还计算并讨论了H4D+的严格零点态，以获得反应H4D+→H3(+) + HD和H2D+ + H2的分支比。使用该PES采用了这种方法，并根据量子零点态的性质进行了评判。最后，描述了一种添加长程相互作用能的简单程序。
