GRID METHOD FOR THE WIGNER FUNCTIONS - APPLICATION TO THE VAN-DER-WAALS SYSTEM AR-H2O
GRID METHOD FOR THE WIGNER FUNCTIONS - APPLICATION TO THE VAN-DER-WAALS SYSTEM AR-H2O
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DOI：
10.1063/1.468455
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发表时间：
1994-11-01
影响因子：
4.4
通讯作者：
LEFORESTIER, C
中科院分区：
文献类型：
--
作者：
LEFORESTIER, C
我们提出了一种方法来来回切换的维格纳函数和相关的三维网格的欧拉角之间的基集。网格-谱变换不是一对一的，因为使用的网格点比维格纳函数多，因此偏离了科斯洛夫的傅立叶方法或莱特和合作者的离散变量表示方法，但这种额外数量的网格点允许人们实现维格纳基集中所有潜在矩阵元素的数值精确积分。作为一个例子，我们应用这种方法来确定H2O-Ar货车van der Waals系统的束缚态，该系统已经由Cohen和Saykally研究过[J. Chem. Phys. 98，6007（1993）]。计算包括耦合的Lanczos计划与分裂表示的哈密顿量。迭代方案制定完全在频谱表示，其中的动能算子项是解析的，潜在的长期评估的网格表示。利用H_2O的刚性转子近似，在工作站上几秒钟的计算时间内得到了所有J=0的束缚态。
We present a method to switch back and forth between a basis set of Wigner functions and an associated three-dimensional grid of Euler angles. The grid-spectral transformation is not one to one as more grid points are used than Wigner functions, and thus departs from the Fourier method of Kosloff or the discrete variable representation method of Light and collaborators, but this extra number of grid points allows one to achieve a numerically exact integration of all the potential matrix elements in the Wigner basis set. As an example, we apply this method to the determination of the bound states of the H2O-Ar van der Waals system, already studied by Cohen and Saykally [J. Chem. Phys. 98, 6007 (1993)]. The calculation consists of coupling a Lanczos scheme with a split representation of the Hamiltonian. The iterative scheme is formulated entirely within the spectral representation in which the kinetic energy operator terms are analytic, the potential term being evaluated in the grid representation. Using the rigid rotor approximation for H2O all the J=0 bound states are obtained in a few seconds of computation time on a workstation.