European Synchrotron Radiation Facility, BP220, F-38043, Grenoble, France.
J Phys Chem B. 2011 Dec 8;115(48):14052-63. doi: 10.1021/jp2037075. Epub 2011 Oct 18.
We present a detailed investigation of the vibrational dynamics of glassy sulfur (g-S). The large frequency range spanned in this study has allowed us to carefully scrutinize the elastic properties of g-S and to analyze their relation to various features of both the glassy and the liquid state. In particular, the acoustic properties of g-S present a quasi-harmonic behavior in the THz frequency range, while at lower frequency, in the GHz range, they are affected by a strong anharmonic contribution. Moreover, the high frequency (THz) dynamics of g-S does not present signatures of the elastic anomalies recently observed in a number of glasses. Despite this apparent contradiction, we show that this finding is not in disagreement with the previous ones. Finally, by considering the correct long wavelength limit of the density fluctuations in the glassy state, we estimate the continuum limit of the nonergodicity factor and we investigate recently proposed relations between the fast dynamics of glasses and the slow dynamics of the corresponding viscous melts.
我们对玻璃态硫（g-S）的振动动力学进行了详细研究。本研究涵盖了较大的频率范围，使我们能够仔细研究 g-S 的弹性性质，并分析它们与玻璃态和液态的各种特征之间的关系。特别是，g-S 的声学性质在太赫兹频率范围内呈现出准谐行为，而在较低频率（GHz 范围内），它们受到强烈的非谐贡献的影响。此外，g-S 的高频（太赫兹）动力学没有表现出最近在许多玻璃中观察到的弹性异常的特征。尽管存在这种明显的矛盾，但我们表明，这一发现与之前的发现并不矛盾。最后，通过考虑玻璃态中密度涨落的正确长波长极限，我们估计了非遍历因子的连续极限，并研究了最近提出的关于玻璃的快速动力学和相应粘性熔体的缓慢动力学之间的关系。
