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Quantum dynamics of vibrational energy flow in oscillator chains driven by anharmonic interactions
New Journal of Physics ( IF 2.8 ) Pub Date : 2020-12-08 , DOI: 10.1088/1367-2630/abc9ed
Raffaele Borrelli 1 , Maxim F Gelin 2
Affiliation  

A new model of vibrational energy transfer in molecular systems taking into account anharmonic (third order) interactions of localized vibrations with a chain of harmonic oscillators is developed. The role of the energy spectrum of the chain and of the magnitude of the non-linear coupling is discussed in detail by an exact numerical solution of the quantum dynamical problem based on the tensor-train (matrix product state) representation of the vibrational wave function. Results show that the type of wave packet motion is determined by the eigen-spectrum of the chain and by its excitation time. It is found that when the excitation of the chain takes place on a much shorter timescale than the energy transfer along the chain the vibrational wave packet moves in a ballistic way independently of the length of the chain. On the other hand when the excitation of the chain takes place on the timescale of the energy transfer along the chain the overall motion becomes superballistic. These findings shed new light on recent observations of ballistic energy transfer along polymethylene chains.



中文翻译:

非谐相互作用驱动振动子链中振动能流的量子动力学

考虑到局部振动与谐波振荡器链的非谐(三阶)相互作用,开发了一种分子系统中振动能量转移的新模型。通过基于振动波函数的张量-应变(矩阵乘积状态)表示的量子动力学问题的精确数值解,详细讨论了链的能谱和非线性耦合的大小的作用。 。结果表明,波包运动的类型取决于链条的本征谱及其激发时间。发现当链的激发发生在比沿链的能量传递短得多的时间尺度上时,振动波包以弹道的方式移动而与链的长度无关。另一方面,当在沿着链条的能量传递的时间尺度上发生链条的激发时,整体运动将成为超弹道。这些发现为最近对沿聚亚甲基链的弹道能量转移的观察提供了新的启示。

更新日期:2020-12-08
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