Johanna Kölbel*, Michael T. Ruggiero*, Shachar Keren, Nimrod Benshalom, Omer Yaffe, J. Axel Zeitler and Daniel M. Mittleman,
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引用次数: 0
Abstract
Ortho-terphenyl (OTP) has long been used as a model system to study the glass transition due to its apparent simplicity and a widespread assumption that it is a rigid molecule. Here, we employ terahertz time-domain spectroscopy and low-frequency Raman spectroscopy to investigate the rigidity of OTP by direct observation of the low-frequency vibrational dynamics. These terahertz phonons involve complex large-amplitude atomic motions where intramolecular and intermolecular displacements are often mixed. Comparison of experimental results with density functional theory and ab initio molecular dynamics simulations shows that the assumption of rigidity neglects important implications for the glass transition and must be revisited. These results highlight the significance of terahertz modes on elasticity, which will be even more critical in more complex systems such as biomolecules.
正三联苯（OTP）因其明显的简单性以及人们普遍认为它是一种刚性分子，长期以来一直被用作研究玻璃化转变的模型体系。在这里，我们采用太赫兹时域光谱和低频拉曼光谱，通过直接观察低频振动动力学来研究 OTP 的刚性。这些太赫兹声子涉及复杂的大振幅原子运动，其中分子内和分子间位移往往混合在一起。实验结果与密度泛函理论和 ab initio 分子动力学模拟的比较表明，刚性假设忽略了对玻璃化转变的重要影响，必须重新审视。这些结果凸显了太赫兹模式对弹性的重要影响，这在生物大分子等更复杂的系统中将更为关键。
期刊介绍：
The Journal of Physical Chemistry (JPC) Letters is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, chemical physicists, physicists, material scientists, and engineers. An important criterion for acceptance is that the paper reports a significant scientific advance and/or physical insight such that rapid publication is essential. Two issues of JPC Letters are published each month.
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