Exploring the dynamics of dimer crossing over a Kramers type potential.
Exploring the dynamics of dimer crossing over a Kramers type potential.
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DOI：
10.1063/1.3675920
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发表时间：
2012-01
期刊：
影响因子：
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通讯作者：
M. Asfaw;Y. Shiferaw
中科院分区：
文献类型：
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作者：
M. Asfaw;Y. Shiferaw
我们利用解析和数值方法探索二聚体穿越势垒的逃逸率。我们发现，对于较小的偶联强度k，势垒跳跃可以很好地近似为两步反应方案，其中一个单体跳过势垒，然后另一个紧随其后。在这种情况下，逃逸率随k的增加而增加，表明单体间的协同作用提高了交叉率。然而，在大耦合强度的极限下，应用绝热消去法，我们发现逃逸率是k的递减函数。因此，我们发现逃逸率是弹簧常数的非单调函数，弹簧常数在最优耦合强度时达到峰值。此外，在弱周期信号存在的情况下，我们表明系统对周期信号的响应在特定的弹簧常数下是明显的，这表明二聚体可以在半周期内快速地在反应坐标上传输。
We explore the escape rate of a dimer crossing a potential barrier using both analytical and numerical approaches. We find that for small coupling strength k, the barrier hopping can be well approximated by a two step reaction scheme where one monomer hops over the barrier and is then followed by the other. In this regime the escape rate increases with k showing that the cooperativity between monomers enhances the crossing rate. However, in the limit of large coupling strength, applying the method of adiabatic elimination, we find that the escape rate is a decreasing function of k. Thus, we find that the escape rate is a non-monotonic function of the spring constant which is peaked at an optimal coupling strength. Furthermore, in the presence of a weak periodic signal, we show that the system response to the periodic signal is pronounced at a particular spring constant showing the dimer can be transported rapidly across the reaction coordinate in a half period.