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Quantum control of photo-chemical isomerization

光化学异构化的量子控制

基本信息

批准号：
13640497
负责人：
FUJIMURA Yuichi
金额：
$ 2.43万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

We have proposed control scenarios for isomerizations that play an important role in photochemical reactions. The basic idea of the quantum control originates from an optimal control theory that was developed in our group. We have applied the control theory to two types of photochemical reactions; IR pulse-induced isomerization of difluorobenzo[c]phenanthrene, and visible laser induced trans-cis isomerization of the retinal chromophore in bacteriorhodopsin.1. Difluorobenzo[c]phenanthrene has herical, molecular chirality. Most of control theories of molecular chirality were restricted to simple systems such as one-dimensional systems with axial chirality. The initial system was assumed to be in an equal mixture of M- and P-forms (racemic mixture). Pure M-form chiral molecules are formed from a racemic mixture by designed two linearly polarized IR laser pulses. These components are p-phase-shifted when the representative points of the isomerization is transferred to the target position a … More long the intrinsic reaction path, while the other representative point remains in its initial potential regime. This results in one-way isomerization control. The research of the molecular chirality control reported here is the first step toward the establishment of a method for controlling herical changes in biomolecules such as DNA.2. A trans-cis isomerization of retinal is a typical example of the potential crossing between the ground and excited states, in which non-adiabatic couplings play an essential role. We have clarified the effects of non-adiabatic couplings on an optimal pathway for the photoisomerization to obtain the control scenario. For this purpose, we considered two cases, strong- and medium-coupling cases. In the former case, most of the initial population of the Franck-Condon packet adiabatically switches to another diabatic potential after initially passing the crossing point. In the latter case, on the other hand, the half of the initial population remains in the original diabatic potential, which is due to non-adiabatic couplings. Less

我们提出了在光化学反应中起重要作用的异构化控制方案。量子控制的基本思想源于我们小组提出的最优控制理论。我们已经将控制理论应用于两种类型的光化学反应；红外脉冲诱导的二氟苯并[c]菲异构化和可见光激光诱导的细菌视紫红质视网膜发色团的反式异构化[j]。二氟苯并[c]菲具有分子手性。分子手性的控制理论大多局限于具有轴向手性的一维体系等简单体系。初始体系假定为M型和p型的等量混合物（消旋混合物）。用设计的两个线偏振红外激光脉冲从外消旋混合物中形成纯m型手性分子。当异构化的代表点转移到目标位置时，这些组分发生p相移。本征反应路径越长，而另一个代表点保持在其初始势区。这导致单向异构化控制。本文报道的分子手性控制研究是建立控制dna等生物分子极性变化方法的第一步。视网膜的反式顺式异构化是基态和激发态之间电位交叉的典型例子，其中非绝热耦合起重要作用。我们已经澄清了非绝热耦合对光异构化最佳途径的影响，以获得控制情景。为此，我们考虑了两种情况，强耦合和中等耦合情况。在前一种情况下，frank - condon包的大多数初始种群在最初通过交叉点后绝热地切换到另一个绝热势。另一方面，在后一种情况下，由于非绝热耦合，初始种群的一半仍然处于原始绝热势中。少