RMT: R-matrix with time-dependence. Solving the semi-relativistic, time-dependent Schrodinger equation for general, multielectron atoms and molecules in intense, ultrashort, arbitrarily polarized laser pulses
RMT: R-matrix with time-dependence. Solving the semi-relativistic, time-dependent Schrodinger equation for general, multielectron atoms and molecules in intense, ultrashort, arbitrarily polarized laser pulses
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DOI：
10.1016/j.cpc.2019.107062
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发表时间：
2020-05-01
影响因子：
6.3
通讯作者：
van der Hart, Hugo W.
中科院分区：
文献类型：
--
作者：
Brown, Andrew C.;Armstrong, Gregory S. J.;van der Hart, Hugo W.
RMT是一个程序，它解决了一般的，多电子原子，离子和分子与激光相互作用的时间相关的薛定谔方程。因此，它可以用来模拟电离（单光子，多光子和强场），电离（高次谐波产生，强场再散射），更一般地说，吸收或散射过程，充分考虑多电子相关效应在一个时间依赖的方式。计算可以进行与超短，强激光脉冲的长波长和任意偏振相互作用的目标。原子的计算可以选择性地包括Breit-Pauli修正项，用于描述相对论（特别是自旋轨道）效应。程序概要程序标题：（RMT）R-矩阵与时间相关程序文件doi：http://dx.doi.org/10.17632/3ptyfg2bmx.1Licensing规定：GPL v3编程语言：Fortran问题性质：激光与物质的相互作用可以用时间相关的薛定谔方程（TDSE）建模。一般的，多电子的原子和分子系统的TDSE的解决方案是计算上的要求，并且以前被限制到特定的激光波长和强度，或简单的，少电子的情况下。RMT通过使用适用于多电子系统以及广泛的微扰和非微扰现象的原子和分子动力学建模通用方法克服了这一限制。解决方法：我们使用R矩阵范式，将相互作用区域划分为“内部”和“外部”区域。在内部区域（在核/核的一些小半径内），充分考虑所有多电子相互作用，包括电子交换和相关。在外部区域，远离原子核/原子核，这些被忽略，一个单一的，电离的电子移动的远程电位的剩余离子系统和激光场。RMT方法的关键计算方面是在每个区域中使用不同的数值方案，在不牺牲精度的情况下促进有效的并行化。给定初始波函数和驱动激光脉冲的电场，使用显式Arnoldi传播子方法计算所有后续时间的波函数和相关的可观测量。其他评论，包括限制和不寻常的功能：原子/分子结构的描述是由其他时间无关的R矩阵代码提供的[1]，[2]，[3]，并且在某种意义上，能力（在结构方面）是从那里继承的。因此，原子计算可以选择性地包括对哈密顿量的布雷特-泡利相对论修正，以考虑自旋轨道效应。然而，对于分子情况，不存在这样的能力。此外，在分子计算中采用了固定核近似（因此忽略了核运动）。同样，所有的计算都局限于描述外层区域的单个电子，因此双电离现象的研究还不在该方法的能力范围内。最后，所采用的并行策略需要使用至少两个（通常更多）计算机核心。因此，没有串行计算的选项，对于大多数现实情况，将需要大规模并行架构（数百个核心）。程序库可在以下网址获得：https：//gitlab.com/UK-amor/RMTReferences [1] C. P. Ballance Parallel R-matrix codes，http://connorb.freeshell.org. [2] R-matrix II codes，http://gitlab.com/uk-amor/rmt/rmatrixii. [3]Z. Masin等人UKRmol+：一套用于模拟分子与电子，正电子和光子相互作用的电子过程的R矩阵方法，COMPUT。物理通讯。，已接受，http：//dx.doi.org/10.1016/j.cpc.2019.107092。(c)2019爱思唯尔B. V.保留所有权利。
RMT is a programme which solves the time-dependent Schrodinger equation for general, multielectron atoms, ions and molecules interacting with laser light. As such it can be used to model ionization (single-photon, multiphoton and strong-field), recollision (high-harmonic generation, strong-field rescattering) and, more generally, absorption or scattering processes with a full account of the multielectron correlation effects in a time-dependent manner. Calculations can be performed for targets interacting with ultrashort, intense laser pulses of long wavelength and arbitrary polarization. Calculations for atoms can optionally include the Breit-Pauli correction terms for the description of relativistic (in particular, spin-orbit) effects.Program summaryProgram Title: (RMT) R-matrix with time-dependenceProgram Files doi: http://dx.doi.org/10.17632/3ptyfg2bmx.1Licensing provisions: GPLv3Programming language: FortranNature of problem: The interaction of laser light with matter can be modelled with the time-dependent Schrodinger equation (TDSE). The solution of the TDSE for general, multielectron atomic and molecular systems is computationally demanding, and has previously been limited either to particular laser wavelengths and intensities, or to simple, few-electron cases. RMT overcomes this limitation by using a general approach to modelling dynamics in atoms and molecules which is applicable to multielectron systems and a wide range of perturbative and non-perturbative phenomena.solution method: We use the R-matrix paradigm, partitioning the interaction region into an 'inner' and an 'outer' region. In the inner region (within some small radius of the nucleus/nuclei), full account is taken of all multielectron interactions including electron exchange and correlation. In the outer region, far from the nucleus/nuclei, these are neglected and a single, ionized electron moves in the long-range potential of the residual ionic system and the laser field. The key computational aspect of the RMT approach is the use of a different numerical scheme in each region, facilitating efficient parallelization without sacrificing accuracy. Given an initial wavefunction and the electric field of the driving laser pulse, the wavefunction for all subsequent times and the associated observables are computed using an explicit, Arnoldi propagator method. Additional comments including restrictions and unusual features: The description of the atomic/molecular structure is provided from other, time-independent R-matrix codes [1], [2], [3], and the capabilities (in terms of structure) are, in some sense, inherited therefrom. Thus, the atomic calculations can optionally include Breit-Pauli relativistic corrections to the Hamiltonian, in order to account for the spinorbit effect. However, no such capability exists for the molecular case. Furthermore, the fixed-nuclei approximation is adopted in the molecular calculations (so nuclear motion is neglected). Similarly, all calculations are restricted to the description of a single electron in the outer region, and consequently the study of double-ionization phenomena is not yet within the capabilities of the method. Finally, the parallel strategy employed necessitates the use of at least two (and usually many more) computer cores. As a result, there is no option for serial calculations and, for most realistic cases, a massively parallel architecture (several hundred cores) will be required. Program repository available at: https://gitlab.com/Uk-amor/RMTReferences[1] C. P. Ballance Parallel R-matrix codes, http://connorb.freeshell.org. [2] R-matrix II codes, http://gitlab.com/uk-amor/rmt/rmatrixii. [3] Z. Masin et al UKRmol+: a suite for modelling of electronic processes in molecules interacting with electrons, positrons and photons using the R-matrix method, Comput. Phys. Commun., accepted, http: //dx.doi.org/10.1016/j.cpc.2019.107092. (c) 2019 Elsevier B.V. All rights reserved.