Vacher Morgane, Bearpark Michael J, Robb Michael A, Malhado João Pedro
Department of Chemistry-Ångström, Uppsala University, Uppsala 75120, Sweden and Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Phys Rev Lett. 2017 Feb 24;118(8):083001. doi: 10.1103/PhysRevLett.118.083001. Epub 2017 Feb 23.
Knowledge about the electronic motion in molecules is essential for our understanding of chemical reactions and biological processes. The advent of attosecond techniques opens up the possibility to induce electronic motion, observe it in real time, and potentially steer it. A fundamental question remains the factors influencing electronic decoherence and the role played by nuclear motion in this process. Here, we simulate the dynamics upon ionization of the polyatomic molecules paraxylene and modified bismethylene-adamantane, with a quantum mechanical treatment of both electron and nuclear dynamics using the direct dynamics variational multiconfigurational Gaussian method. Our simulations give new important physical insights about the expected decoherence process. We have shown that the decoherence of electron dynamics happens on the time scale of a few femtoseconds, with the interplay of different mechanisms: the dephasing is responsible for the fast decoherence while the nuclear overlap decay may actually help maintain it and is responsible for small revivals.
了解分子中的电子运动对于我们理解化学反应和生物过程至关重要。阿秒技术的出现为诱导电子运动、实时观察电子运动并可能对其进行操控开辟了可能性。一个基本问题仍然是影响电子退相干的因素以及核运动在此过程中所起的作用。在这里，我们使用直接动力学变分多组态高斯方法对电子和核动力学进行量子力学处理，模拟了多原子分子对二甲苯和改性双亚甲基金刚烷电离后的动力学过程。我们的模拟为预期的退相干过程提供了新的重要物理见解。我们已经表明，电子动力学的退相干发生在几飞秒的时间尺度上，这是不同机制相互作用的结果：去相位导致快速退相干，而核重叠衰减实际上可能有助于维持退相干，并导致小的复苏。
