Wavepacket Dynamics of Ultrafast Chemical Processes

1.光缔合过程中的分子振动冷却：通过对二次啁啾脉冲光缔合反应的波包计算，实现了产物OH分子的振动冷却。啁啾相干拉曼光谱：基于二阶微扰理论，推导了在啁啾激光脉冲存在下分子体系的自发和受激拉曼散射的解析公式。Xe在氧化Si(100)表面的光激发脱附：对Xe/氧化Si(100)体系在电子基态和激发态下的势能面进行了从头算CASSCF计算，以阐明光刺激脱附的机理，并基于波包计算分析了平动能分布。量子速率常数的通量-通量互相关函数法：我们使用通量-通量互相关法(CCFA)来计算反应的量子热速率常数，而自相关函数法(ACFA)不能很好地应用于这些反应，封闭的分割面和CCFA的组合给出了明确定义的单跳和多跳速率常数。松弛状态下的人口迁移：实现完全人口反转是一种控制。在本研究中，我们发现，对于激光的持续时间，比正啁啾效应更重要的机制是可以任意确定的，并且可以选择啁啾速率。这一结论证明了在超快弛豫存在下完全反转布居的可能性。

1. Molecular Vibrational Cooling via Photoassociation Process :Wavepacket calculations on the O+H photoassociation reaction with a quadratic-chirped pulse have achieved the vibrational cooling of the product OH molecule.2. Chirped Coherent Raman Spectroscopy :On the basis of a second-order perturbation theory, analytical formulas are derived for describing spontaneous and stimulated Raman scatterings of a molecular system in the presence of chirped laser pulse.3. Photo-stimulated Desorption of Xe from an Oxidized Si(100) Surface :Ab initio CASSCF calculations for the potential energy surfaces of the Xe/oxidized Si(100) system in the electronic ground and excited states are performed in order to clarify the mechanism of photo-stimulated desorption and the translational energy distribution is analyzed based on wavepacket calculations.4. Flux-Flux Cross-Correlation Function Approach to Quantum Rate Constants :We employ a flux-flux cross-correlation approach (CCFA) to calculate quantum thermal rate constants of reactions to which an auto-correlation function approach ACFA) is not adequate to be applied, A combination of closed dividing surfaces and CCFA gives well-defined rate constants for both single and multi-hopping rates.5. Population Transfer in the Presence of Relaxation :Achievement of complete population inversion is one of control. In this study, we found that the mechanism important than that of positive-chirp effect for duration of a laser can be arbitrarily determined and chirp rate are chosen. This conclusion demonstrates a possibility of complete population inversion in the presence of ultrafast relaxation.