Quantics: A general purpose package for Quantum molecular dynamics simulations
Quantics: A general purpose package for Quantum molecular dynamics simulations
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DOI：
10.1016/j.cpc.2019.107040
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发表时间：
2020-03
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通讯作者：
Graham A Worth
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作者：
Graham A Worth
Quantics是一个通用程序包，通过求解含时薛定谔方程来模拟分子系统的时间演化。主要的代码是基于多组态时间相关哈特里（MCTDH）算法的各种变体，包括强大的多层MCTDH算法，已被用来传播波函数高达1000自由度。MCTDH使用传统的离散基集表示的哈密顿量和波函数的收缩，和Quantics包括一系列的变量表示（DVR）网格基集和配置方法。输入是通过ASPLAN文本文件和分子与分析势函数没有编程是必需的。包含潜在函数库以处理更复杂的情况，并且可以根据用户的需要添加更多函数。该代码还包括变分多构型高斯（vMCG）方法，该方法基于波函数的高斯波包展开。vMCG可以以“直接”方式（DD-vMCG）运行，使用许多量子化学程序实时计算势能面。除了波包传播之外，Quantics还可以求解小系统的与时间无关的薛定谔方程，并可以求解Liouville-von-Neumann方程来传播密度矩阵。该软件包包括辅助程序，以帮助建立计算和分析输出。Quantics是英国量子动力学合作计算项目（CCPQ）和欧洲E-CAM项目的社区代码，E-CAM项目是由欧洲原子与分子计算中心（CECAM）运行的软件开发电子基础设施。通过这一点，它已成为一个框架，为一般的动力学代码，例如使外部表面跳跃代码使用的Quantics输入和操作员界面。程序摘要程序标题：Quantics程序文件doi：http://dx.doi.org/10.17632/x9dcpc2r5c.1Licensing规定：LGPLv 3编程语言：Fortran 90。一些Fortran 77，Fortran 2003，C和python。问题的性质：求解一组原子核的含时薛定谔方程允许研究一系列物理过程，包括所有的量子效应。这允许实验信号被给予分子解释。典型的应用是散射截面或时间分辨光谱，但速率常数和其他传输特性也是可能的。要解决的确切问题由必须由用户提供的哈密顿量和再次由用户定义的初始波包定义。对波包演化的最终分析提供了实验信号或分子性质。求解方法：有一系列的方法可以求解波包的时间演化（见正文）。这些可以被广泛地描述为基集方法，其中波包和哈密顿量在一组函数中展开。各种函数都是可能的，包括基于网格的集合（DVR和配置）和高斯波包。然后，波包可以使用各种算法来传播，这取决于所选择的表示。这些包括完整的数值精确解，各种版本的多组态时间相关的Hartree方法和近似方法，如轨迹表面跳跃。完整的细节在软件包提供的文档、一本书和一些评论文章中给出[1，2，3]。其他注释包括限制和不寻常的功能：代码已经在一些Linux发行版和编译器上测试过。它的工作...
Quantics is a general purpose program package to simulate the time-evolution of a molecular system by solving the time-dependent Schrödinger equation. The main code is based on the multi-configurational time-dependent Hartree (MCTDH) algorithm in various variants, including the powerful multilayer-MCTDH algorithm that has been used to propagate a wavefunction for up to 1000 degrees of freedom. MCTDH uses a contraction of traditional discrete basis set representations of the Hamiltonian and wavefunction, andQuanticsincludes a range of variable representation (DVR) grid basis sets and collocation methods. Input is via ascii text files and for molecules with analytical potential functions no programming is required. A library of potential functions is included to treat more complicated cases, and more functions can be added as required by the user. The code also includes the variational multi-configurational Gaussian (vMCG) method that is based on a Gaussian wavepacket expansion of the wavefunction. vMCG can be run in a “direct” manner (DD-vMCG), calculating the potential energy surfaces on-the-fly using a number of quantum chemistry programs. In addition to wavepacket propagation, Quantics can solve the time-independent Schrödinger equation for small systems and can solve the Liouville–von-Neumann equation to propagate density matrices. The Package includes auxiliary programs to help set up calculations and analyse the output. Quantics is a community code of the UK Collaborative Computational Project for Quantum Dynamics (CCPQ) and the European E-CAM project, an e-infrastructure for software development run by the Centre Européen de Calcul Atomique et Moléculaire (CECAM). Through this it has become a framework for general dynamics codes, for example enabling an external surface hopping code to use theQuanticsinput and operator interfaces.Program summaryProgram Title:QuanticsProgram Files doi:http://dx.doi.org/10.17632/x9dcpc2r5c.1Licensing provisions:LGPLv3Programming language:Fortran90. Some Fortran77, Fortran2003, C and python.Nature of problem:Solving the time-dependent Schrödinger equation for a set of nuclei allows a range of physical processes to be studied including all quantum effects. This allows an experimental signal to be given a molecular interpretation. Typical applications are scattering cross-sections or time-resolved spectra, but also rate constants and other transport properties are possible. The exact problem to be solved is defined by the Hamiltonian, which must be provided by the user, and the initial wavepacket, again defined by the user. The final analysis of the evolving wavepacket then provides the experimental signal or molecular property.Solution method:A range of methods are possible for solving the time-evolution of a wavepacket (see main text). These can be broadly described as basis-set methods, in which the wavepacket and Hamiltonian are expanded in a set of functions. Various functions are possible, including grid-based sets (DVRs and collocation), and Gaussian wavepackets. The wavepacket can then be propagated using a variety of algorithms depending on the representation chosen. These include the full numerically-exact solution, various versions of the multi-configurational time-dependent Hartree method and approximate methods such as trajectory surface hopping. Full details are given in the documentation provided with the package and in a book and a number of review articles [1,2,3].Additional comments including restrictions and unusual features:The code has been tested on a number of linux distributions and compilers. It works …