Vispa A, Romanini M, Ramos M A, Pardo L C, Bermejo F J, Hassaine M, Krivchikov A I, Taylor J W, Tamarit J Ll
Grup de Caracterització de Materials, Departament de Física, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Eduard Maristany, 10-14, 08019 Barcelona, Catalonia, Spain.
Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Francisco Tomás y Valiente 7, 28049 Madrid, Spain.
Phys Rev Lett. 2017 Mar 10;118(10):105701. doi: 10.1103/PhysRevLett.118.105701. Epub 2017 Mar 7.
We present a dynamic and thermodynamic study of the orientational glass former Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane, CCl_{2}F-CClF_{2}) in order to analyze its kinetic and thermodynamic fragilities. Freon 113 displays internal molecular degrees of freedom that promote a complex energy landscape. Experimental specific heat and its microscopic origin, the vibrational density of states from inelastic neutron scattering, together with the orientational dynamics obtained by means of dielectric spectroscopy have revealed the highest fragility value, both thermodynamic and kinetic, found for this orientational glass former. The excess in both Debye-reduced specific heat and density of states (boson peak) evidences the existence of glassy low-energy excitations. We demonstrate that early proposed correlations between the boson peak and the Debye specific heat value are elusive as revealed by the clear counterexample of the studied case.
我们对取向玻璃形成剂氟利昂113（1,1,2 - 三氯 - 1,2,2 - 三氟乙烷，CCl₂F - CClF₂）进行了动力学和热力学研究，以分析其动力学和热力学脆弱性。氟利昂113表现出促进复杂能量景观的内部分子自由度。实验比热及其微观起源、非弹性中子散射的振动态密度，以及通过介电谱获得的取向动力学，揭示了该取向玻璃形成剂在热力学和动力学方面的最高脆弱性值。德拜约化比热和态密度（玻色子峰）的过量证明了玻璃态低能激发的存在。我们证明，正如所研究案例的明显反例所示，早期提出的玻色子峰与德拜比热值之间的相关性难以捉摸。
