Quantum Dynamics and Laser Control for Photochemistry
Quantum Dynamics and Laser Control for Photochemistry
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光化学的量子动力学和激光控制
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
M. Sala
中科院分区：
文献类型：
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作者：
M. Sala
本论文的中心课题是对化学感兴趣的分子系统中的超快动力学过程及其激光脉冲控制的理论描述。我们首先利用电子结构计算研究苯胺的光化学。本文报道了电子低能级势能面的一些以前未知的特征，并结合已有的实验结果进行了分析。我们采用量子动力学模拟方法，基于一个包含四个最低激发电子态和十六个振动模的模型哈密顿量，研究了吡嗪的光化学行为。研究表明，暗态Au（nπ介子）在分子光激发后的超快动力学过程中起着重要的作用.用简化的艾德二态四模模型哈密顿量研究了吡嗪激发态动力学的激光控制。提出了一种利用强非共振激光脉冲诱导的Stark效应来提高B2u（π）亮态寿命的控制机制.我们最终专注于NHD 2分子的隧道动力学的激光控制，使用精确的全维势能和偶极矩表面。我们使用简单的等效哈密顿量来探索激光参数对动力学的影响，并设计合适的激光场来实现控制。这些激光场随后被用于MCTDH量子动力学模拟。在我们的模型中实现了隧道效应的增强和抑制。
The central subject of this thesis is the theoretical description of ultrafast dynamical processes in molecular systems of chemical interest and of their control by laser pulses. We first use electronic structure calculations to study the photochemistry of aniline. A umber of previously unknown features of the potential energy surfaces of the low-lying elec-tronic states are reported, and analyzed in relation with the experimental results available. We use quantum dynamics simulations, based on a model Hamiltonian including the four lowest excited electronic states and sixteen vibrational modes, to investigate the photochem-istry of pyrazine. We show that the dark Au(nπ∗) state plays an important role in the ultrafast dynamics of the molecule after photoexcitation. The laser control of the excited state dynamics of pyrazine is studied using a simplified two-state four-mode model Hamiltonian. We propose a control mechanism to enhance the lifetime of the bright B2u(ππ∗) state using the Stark effect induced by a strong non-resonant laser pulse. We finally focus on the laser control of the tunneling dynamics of the NHD2 molecule, using accurate full-dimensional potential energy and dipole moment surfaces. We use simple effective Hamiltonians to explore the effect of the laser parameters on the dynamics and design suitable laser fields to achieve the control. These laser fields are then used in MCTDH quantum dynamics simulations. Both enhancement and suppression of tunneling are achieved in our model.