Han Hui-li, Li Yong, Zhang Xian-zhou, Shi Ting-yun
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
J Chem Phys. 2007 Oct 21;127(15):154104. doi: 10.1063/1.2795714.
We calculate the L=0 vibration energies and rotational constants for the van der Waals trimers 20NeAr2, 20Ne2Ar, and their corresponding isotopologues within the framework of hyperspherical coordinates. The Schrodinger equation in hyperangular coordinates is solved at a series of fixed hyper-radii using B-splines and the resulting coupled hyper-radial equation is solved using the slow variable discretization method developed by Tolstikhin et al. [J. Phys. B 29, L389 (1996)]. Using the special properties of B-splines, we make the knot distributions more precisely, characterizing the behavior of channel functions. Our method improves the convergence greatly. It turns out that our numerical tool works quite well in study of rare gas trimers. Calculations are performed on two kinds of pair potentials, the HFD-B and Tang-Toennies (TT) potentials, and the resultant rotational constants and their isotope shifts are compared with the experimental results obtained from high-resolution spectroscopy. The TT pair potentials give much better agreement with the experimental values for 20Ne2Ar and 22Ne2Ar trimers, while the HFD-B pair potentials give much better agreement with the experimental values for 20NeAr2 and 22NeAr2 trimers.
我们在超球坐标框架内计算了范德华三聚体(20NeAr2)、(20Ne2Ar)及其相应同位素异构体的(L = 0)振动能量和转动常数。使用(B)样条在一系列固定超半径下求解超角坐标中的薛定谔方程，并使用托尔斯蒂欣等人[《物理学报B》29，L389 (1996)]开发的慢变量离散化方法求解由此产生的耦合超径向方程。利用(B)样条的特殊性质，我们更精确地确定了节点分布，表征了通道函数的行为。我们的方法大大提高了收敛性。结果表明，我们的数值工具在稀有气体三聚体的研究中表现良好。计算是在两种对势，即HFD - B和唐 - 托尼斯（TT）势上进行的，并将所得的转动常数及其同位素位移与从高分辨率光谱学获得的实验结果进行比较。对于(20Ne2Ar)和(22Ne2Ar)三聚体，TT对势与实验值的吻合度更好，而对于(20NeAr2)和(22NeAr2)三聚体，HFD - B对势与实验值的吻合度更好。
