A Phenomenological Description of the PALS Response in Glass - Forming Systems

摘要：

A phenomenological description of the ortho-positronium (o-Ps) response from positron annihilation spectroscopy (PALS) and the dynamics from viscosity studies on two typical glassforming compounds within the framework of the two-order parameter (TOP) model is presented. The dynamical data are accounted for by the modified Vogel - Fulcher - Tamman -Hesse (MVFTH) equation. Subsequently, the quasi-sigmoidal course of the o-Ps lifetime, τ3, with or without the high-temperature plateau region as a function of the temperature over a wide temperature range can be described by an effective free volume version of the TOP model. This simultaneous description suggests a close relationship between the PALS response and the dynamics of supercooled liquids and seems to support the liquid -like and solid -like domain physical picture of all the three physical states of the disordered phase of the condensed systems.

关键词： glass-forming compounds positron annihilation lifetime spectroscopy viscosity phenomenological description

作者: Josef Barto(s)

作者单位: Polymer Institute of the Slovak Academy of Sciences,Dúbravská cesta 9,SK - 842 36 Bratislava,Slovakia

会议类型: 国际会议

会议名称: 第九届国际正电子与正电子素国际会议(9th International Workshop on Positron and Positronium Chemistry)(PPC–9)

会议地点: 武汉

会议语种:英文

页码: 48-52

在线出版日期: 2008-05-11（万方平台首次上网日期，不代表论文的发表时间）