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arXiv 1902.08489physics.chem-ph
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基于矩阵乘积态的超快从头计算量子化学

Ultrafast ab-initio Quantum Chemistry Using Matrix Product States

Lars-Hendrik Frahm, Daniela Pfannkuche

摘要:

化学系统中的超快动力学为在分子尺度上研究基本过程提供了独特的途径。由于问题的量子性质,对这种系统的适当描述通常非常具有挑战性。近年来,矩阵乘积态(MPS)的概念在描述这种关联量子系统方面得到了广泛的应用。在这项工作中,我们继续发展MPS方法来研究量子化学系统中的超快电子动力学。该方法将四阶Runge-Kutta和Krylov时空演化等时间演化格式与MPS相结合,有效求解含时薛定谔方程。这允许在激发后的几个飞秒内在完全构型相互作用(CI)水平上描述分子中的电子动力学。作为一个基准,我们比较MPS为基础的计算全CI计算的一个链的氢原子和水分子。Krylov时空演化特别适合于MPS方法,因为它提供了广泛的机会来调整到减少MPS维度的情况。最后,我们应用MPS方法来描述碘乙炔中的电荷迁移效应,并发现我们的结果和实验观察之间的直接协议。

英文摘要:

Ultrafast dynamics in chemical systems provide a unique access to fundamental processes at the molecular scale. A proper description of such systems is often very challenging because of the quantum nature of the problem. The concept of matrix product states (MPS), however, has proven its performance in describing such correlated quantum system in recent years for a wide range of applications. In this work, we continue the development of the MPS approach to study ultrafast electron dynamics in quantum chemical systems. The method combines time evolution schemes, such as fourth-order Runge-Kutta and Krylov space time evolution, with MPS, in order to solve the time-dependent Schrödinger equation efficiently. This allows for describing electron dynamics in molecules on a full configurational interaction (CI) level for a few femtoseconds after excitation. As a benchmark, we compare MPS based calculations to full CI calculations for a chain of hydrogen atoms and for the water molecule. Krylov space time evolution is in particular suited for the MPS approach, as it provides a wide range of opportunities to be adjusted to the reduced MPS dimension case. Finally, we apply the MPS approach to describe charge migration effects in iodoacetylene and find direct agreement between our results and experimental observations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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