Activated chemistry in the presence of a strongly symmetrically coupled vibration
Activated chemistry in the presence of a strongly symmetrically coupled vibration
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DOI：
10.1063/1.475756
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发表时间：
1998-03-01
影响因子：
4.4
通讯作者：
Schwartz, SD
中科院分区：
文献类型：
--
作者：
Antoniou, D;Schwartz, SD
在气相中，如Benderskii及其同事所强调的，如果反应坐标对称地耦合到谐波振荡，则隧道反应速率可以显著增强[Adv.Chem.Phys.88，1（1994）]。这是由于对称耦合导致势垒高度调制的事实。在模型凝聚相研究中的反应中也观察到类似的效应，如Borgis和Hynes [J. Chem.Phys.94，3619（1991）]和苏亚雷斯和Silbey [J. Chem.Phys.94，4809（1991）]所研究的哈密顿量。所有这些工作都假设隧穿是从基态开始的。在本文中，我们使用的指数重算技术，我们在我们最近的工作中使用的量子Kramers问题，研究的情况下，可以有激发到更高的状态和激活传输的障碍。我们提出了一个一般的方法，以准确地包括反应坐标和对称耦合促进振动之间的直接耦合，并发现在凝聚相的反应速率增强的情况下，从基态隧穿。然而，这种效果，强烈调制的凝聚相环境引起的相干性损失。(C)1998年美国物理学会。
In the gas phase, tunneling reaction rates can be significantly enhanced if the reaction coordinate is symmetrically coupled to a harmonic oscillation, as has been emphasized by Benderskii and co-workers [Adv. Chem. Phys. 88, 1 (1994)]. This is due to the fact that the symmetric coupling leads to modulation of the barrier height. Similar effects have been observed in reactions in model condensed phase studies, as in the Hamiltonians that have been studied by Borgis and Hynes [J. Chem. Phys. 94, 3619 (1991)] and Suarez and Silbey [J. Chem. Phys. 94, 4809 (1991)]. All of these works assume that tunneling proceeds from the ground state. In this paper, we use the exponential resummation technique that we used in our recent work on the quantum Kramers problem, to study the case when there can be excitations to higher states and activated transmission over a barrier. We present a general methodology to exactly include direct coupling between the reaction coordinate and the symmetrically coupled promoting vibration and find that the rate of reactions in condensed phases is enhanced as in the case of tunneling from the ground state. This effect, however, is strongly modulated by loss of coherence induced by the condensed phase environment. (C) 1998 American Institute of Physics.