Instituto Tecnológico de Toluca, Av. Tecnológico s/n, Metepec 52140, Edo. Mex., Apartado Postal 890, Mexico.
J Chem Phys. 2010 Jan 28;132(4):044301. doi: 10.1063/1.3298586.
Transition probabilities on the interaction of the ground and the lowest excited states of gold Au ((2)S:5d(10)6s(1), (2)D:5d(9)6s(2), and (2)P:5d(10)6p(1)) with silane (SiH(4)) are studied through ab initio Hartree-Fock self-consistent field calculations, where the atom's core is represented by relativistic effective core potentials. These calculations are followed by a multiconfigurational self-consistent field study. The correlation energy is accounted for through extensive variational and perturbative second order multireference Moller-Plesset configuration interaction analysis of selected perturbations obtained by iterative process calculations using the CIPSI program package. It is found that the Au atom in the ((2)P:5d(10)6p(1)) state inserts in the Si-H bond. In this interaction its corresponding D (2)A(') potential energy surface is initially attractive and only becomes repulsive after encountering an avoided crossing with the initially repulsive C (2)A(') surface linked to the Au((2)D:5d(9)6s(2))-SiH(4) fragments. The A, B, and C (2)A(') curves derived from the Au((2)D:5d(9)6s(2)) atom interaction with silane are initially repulsive, each one of them showing two avoided crossings, while the A (2)A(') curve goes sharply downwards until it meets the X (2)A(') curve interacting adiabatically, which is linked with the Au((2)S:5d(10)6s(1))-SiH(4) moieties. The A (2)A(') curve becomes repulsive after the avoided crossing with the X (2)A('), curve. The lowest-lying X (2)A(') potential leads to the HAuSiH(3) X (2)A(') intermediate molecule. This intermediate molecule, diabatically correlated with the Au((2)P:5d(10)6p(1))+SiH(4) system which lies 3.34 kcal/mol above the ground state reactants, has been carefully characterized as have the dissociation channels leading to the AuH+SiH(3) and H+AuSiH(3) products. These products are reached from the HAuSiH(3) intermediate without any activation barrier. The Au-SiH(4) calculation results are successfully compared to experiment. Landau-Zener theory of avoided crossings is applied to these interactions considering the angle theta instead of the distance r as the reaction coordinate.
通过从头算哈特利-福克自洽场计算研究了金 Au((2)S:5d(10)6s(1)、(2)D:5d(9)6s(2) 和 (2)P:5d(10)6p(1))与硅烷 (SiH(4)) 的基态和最低激发态之间的相互作用的跃迁概率，其中原子的核心由相对论有效核势表示。这些计算之后是多组态自洽场研究。通过迭代过程计算使用 CIPSI 程序包获得的选定微扰的广泛变分和微扰二阶多参考 Møller-Plesset 组态相互作用分析来考虑相关能量。发现 Au 原子在 ((2)P:5d(10)6p(1)) 态中插入 Si-H 键中。在这种相互作用中，其相应的 D(2)A(')势能表面最初是吸引人的，并且仅在与最初排斥的与 Au((2)D:5d(9)6s(2))-SiH(4)片段相关联的 C(2)A(')表面相遇后才变得排斥。从 Au((2)D:5d(9)6s(2))原子与硅烷相互作用中得出的 A、B 和 C(2)A(')曲线最初是排斥的，每个曲线都有两个回避交叉，而 A(2)A(')曲线急剧下降，直到与绝热相互作用的 X(2)A(')曲线相遇，该曲线与 Au((2)S:5d(10)6s(1))-SiH(4)部分相关联。A(2)A(')曲线在与 X(2)A(')曲线的回避交叉之后变得排斥。最低的 X(2)A(')势能导致 HAuSiH(3) X(2)A(')中间分子。这个中间分子与 Au((2)P:5d(10)6p(1))+SiH(4)系统在 3.34 kcal/mol 以上的基态反应物绝热相关，已经被仔细地描述为导致 AuH+SiH(3)和 H+AuSiH(3)产物的离解通道。这些产物从 HAuSiH(3)中间产物没有任何活化能垒到达。Au-SiH(4)计算结果与实验成功比较。考虑到角度θ而不是距离 r 作为反应坐标，将 Landau-Zener 理论应用于这些相互作用中的避免交叉。
