Trung Nguyen Thanh, Duong Nguyen Thuy, Hien Nguyen Quoc, Tap Tran Duy, Thanh Nguyen Duc
Institute of Physics, Vietnam Academy of Science and Technology, Ba Dinh, Hanoi, Vietnam.
Vietnam Japan University, Vietnam National University, Hanoi, Vietnam.
Sci Rep. 2023 Aug 22;13(1):13707. doi: 10.1038/s41598-023-40901-3.
In this work, we present the results of the ortho-positronium (o-Ps) annihilation lifetimes and nitrogen adsorption measurements for different porous materials and an approach for describing the annihilation of o-Ps in a pore, which results in a surface-volume formula (SVF) for calculating the pore-related o-Ps lifetime. This proposed formula gives the relationship between the o-Ps annihilation rate and the effective pore radius, bulk composition, and pore structure, including pore geometry and topology. The pore-related o-Ps lifetimes of different materials calculated by the SVF are consistent with experimental results for both micro- and mesopores (and macropores) with different geometries and topologies. The SVF is convenient for calculations of pore dimensions for many cases of metal organic frameworks and zeolites. This approach enables us to fully explain the temperature dependence of the o-Ps annihilation lifetime over a wide temperature range, 20-700 K.
在这项工作中，我们展示了不同多孔材料的正电子素（o-Ps）湮没寿命和氮吸附测量结果，以及一种描述o-Ps在孔隙中湮没的方法，该方法得出了一个用于计算与孔隙相关的o-Ps寿命的表面-体积公式（SVF）。这个提出的公式给出了o-Ps湮没率与有效孔隙半径、本体组成以及孔隙结构（包括孔隙几何形状和拓扑结构）之间的关系。通过SVF计算得到的不同材料的与孔隙相关的o-Ps寿命，与具有不同几何形状和拓扑结构的微孔、介孔（以及大孔）的实验结果一致。SVF便于计算许多金属有机框架和沸石情况下的孔隙尺寸。这种方法使我们能够在20 - 700 K的宽温度范围内充分解释o-Ps湮没寿命的温度依赖性。
