Theoretische Chemie, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
J Chem Phys. 2012 Mar 28;136(12):124119. doi: 10.1063/1.3698308.
A rigorous and efficient approach for the calculation of eigenstates in polyatomic molecular systems with potentials displaying multiple wells is introduced. The scheme is based on the multi-configurational time-dependent Hartree (MCTDH) approach and uses multiple MCTDH wavefunctions with different single-particle function bases to describe the quantum dynamics in the different potential wells. More specifically, an iterative block Lanczos-type diagonalization scheme utilizing state-averaged MCTDH wavefunctions localized in different wells is employed to obtain the energy eigenvalues and eigenstates. The approach does not impose any formal restriction on the symmetry of the potential or the number of wells. A seven-dimensional model system of tetrahedral symmetry, which is inspired by A·CH(4) type complexes and displays four equivalent potential minima, is used to study the numerical performance of the new approach. It is found that the number of configurations in the MCTDH wavefunctions required to obtain converged results is decreased by roughly one order of magnitude compared to standard MCTDH calculations employing a block-relaxation scheme.
本文提出了一种在具有多个势阱的多原子分子体系中计算本征态的严格高效方法。该方案基于多组态含时哈特里（MCTDH）方法，并使用具有不同单粒子函数基的多个 MCTDH 波函数来描述不同势阱中的量子动力学。更具体地说，利用在不同阱中局域化的态平均 MCTDH 波函数，采用迭代块 Lanczos 型对角化方案来获得能量本征值和本征态。该方法不对势或阱数的对称性施加任何形式的限制。一个具有四面体对称性的七维模型系统，它受到 A·CH(4) 型配合物的启发，并显示出四个等效的势能极小值，被用来研究新方法的数值性能。结果表明，与采用块松弛方案的标准 MCTDH 计算相比，获得收敛结果所需的 MCTDH 波函数中的构型数减少了大约一个数量级。
