Elrod M J, Saykally R J
Department of Chemistry, University of California, Berkeley 94720, USA.
J Chem Phys. 1995 Jul 15;103(3):933-49. doi: 10.1063/1.469794.
An accurate and detailed semiempirical intermolecular potential energy surface for (HCl)2 has been determined by a direct nonlinear least-squares fit to 33 microwave, far-infrared and near-infrared spectroscopic quantities using the analytical potential model of Bunker et al. [J. Mol. Spectrosc. 146, 200 (l99l)] and a rigorous four-dimensional dynamical method (described in the accompanying paper). The global minimum (De= -692 cm-1) is located near the hydrogen-bonded L-shaped geometry (R=3.746 angstroms, theta1=9 degrees, theta2=89.8 degrees, and phi=180 degrees). The marked influence of anisotropic repulsive forces is evidenced in the radial dependence of the donor-acceptor interchange tunneling pathway. The minimum energy pathway in this low barrier (48 cm-1) process involves a contraction of 0.1 angstroms in the center of mass distance (R) at the C2h symmetry barrier position. The new surface is much more accurate than either the ab initio formulation of Bunker et al. or a previous semiempirical surface [J. Chem. Phys. 78, 6841 (1983)].
通过使用邦克等人的分析势模型[《分子光谱学杂志》146, 200 (1991)]以及一种严格的四维动力学方法（在随附论文中描述），对33个微波、远红外和近红外光谱量进行直接非线性最小二乘法拟合，确定了(HCl)₂精确且详细的半经验分子间势能面。全局最小值（De = -692 cm⁻¹）位于氢键结合的L形几何结构附近（R = 3.746埃，θ₁ = 9度，θ₂ = 89.8度，且φ = 180度）。供体 - 受体交换隧穿途径的径向依赖性证明了各向异性排斥力的显著影响。在这个低势垒（48 cm⁻¹）过程中的最小能量途径涉及在C₂h对称势垒位置质心距离（R）收缩0.1埃。新的势能面比邦克等人的从头算公式或先前的半经验势能面[《化学物理杂志》78, 6841 (1983)]都要精确得多。
