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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Control of chemical dynamics by lasers: Theoretical considerations
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Control of chemical dynamics by lasers: Theoretical considerations

机译：激光控制化学动力学的理论考虑

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摘要

Theoretical ideas are proposed for laser control of chemical dynamics. There are the following three elementary processes in chemical dynamics: (i) motion of the wave packet on a single adiabatic potential energy surface, (ii) excitation/de-excitation or pump/dump of wave packet, and (iii) nonadiabatic transitions at conical intersections of potential energy surfaces. A variety of chemical dynamics can be controlled, if we can control these three elementary processes as we desire. For (i) we have formulated the semiclassical guided optimal control theory, which can be applied to multidimensional real systems. The quadratic or periodic frequency chirping method can achieve process (ii) with high efficiency close to 100%. Concerning process (iii) mentioned above, the directed momentum method, in which a predetermined momentum vector is given to the initial wave packet, makes it possible to enhance the desired transitions at conical intersections. In addition to these three processes, the intriguing phenomenon of complete reflection in the nonadiabatic-tunneling-type of potential curve crossing can also be used to control a certain class of chemical dynamics. The basic ideas and theoretical formulations are provided for the above-mentioned processes. To demonstrate the effectiveness of these controlling methods, numerical examples are shown by taking the following processes: (a) vibrational photoisomerization of HCN, (b) selective and complete excitation of the fine structure levels of K and Cs atoms, (c) photoconversion of cyclohexadiene to hexatriene, and (d) photodissociation of OHCl to O + HCl.
机译：提出了用于化学动力学的激光控制的理论思想。化学动力学中有以下三个基本过程：（i）波包在单个绝热势能面上的运动;（ii）波包的激发/消磁或泵浦/转储;以及（iii）在非绝热跃迁处势能面的圆锥形交点。如果我们可以根据需要控制这三个基本过程，则可以控制多种化学动力学。对于（i），我们已经制定了半经典指导的最优控制理论，该理论可以应用于多维实际系统。二次或周期频率线性调频方法可以以接近100％的高效率实现过程（ii）。关于上述过程（iii），其中将预定动量矢量给予初始波包的有向动量法使得可以增强圆锥形相交处的期望过渡。除了这三个过程外，在非绝热隧穿型势曲线交叉中发生的完全反射的有趣现象也可以用于控制某一类化学动力学。提供了上述过程的基本思想和理论公式。为了证明这些控制方法的有效性，通过以下过程显示了数值示例：（a）HCN的振动光异构化;（b）K和Cs原子的精细结构能级的选择性和完全激发;（c）HCN的光转化环己二烯为己三烯，以及（d）OHCl光解为O + HCl。

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