Zubiaga Asier, Warringham Robbie, Mitchell Sharon, Gerchow Lars, Cooke David, Crivelli Paolo, Pérez-Ramírez Javier
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093, Zurich, Switzerland.
Institute for Particle Physics, Department of Physics, ETH Zurich, Otto-Stern-Weg 5, 8093, Zurich, Switzerland.
Chemphyschem. 2017 Mar 3;18(5):470-479. doi: 10.1002/cphc.201601258. Epub 2017 Jan 18.
Positron annihilation spectroscopy (PAS) is a powerful method to study the size and connectivity of pores in zeolites. The lifetime of positronium within the host material is commonly described by the Tao-Eldrup model. However, one of its largest limitations arises from the simple geometries considered for the shape of the pores, which cannot describe accurately the complex topologies in zeolites. Here, an atomic model that combines the Tao potential with the crystallographic structure is introduced to calculate the distribution and lifetime of Ps intrinsic to a given framework. A parametrization of the model is undertaken for a set of widely applied zeolite framework types (*BEA, FAU, FER, MFI, MOR, UTL), before extending the model to all known structures. The results are compared to structural and topological descriptors, and to the Tao-Eldrup model adapted for zeolites, demonstrating the intricate dependence of the lifetime on the pore architecture.
正电子湮没光谱法（PAS）是研究沸石中孔的大小和连通性的一种强大方法。主体材料中正电子素的寿命通常用陶-埃尔德鲁普模型来描述。然而，其最大的局限性之一源于所考虑的孔形状的简单几何结构，这种结构无法准确描述沸石中的复杂拓扑结构。在此，引入了一种将陶势与晶体结构相结合的原子模型，以计算给定骨架中固有正电子素的分布和寿命。在将该模型扩展到所有已知结构之前，对一组广泛应用的沸石骨架类型（BEA、FAU、FER、MFI、MOR、UTL）进行了模型参数化。将结果与结构和拓扑描述符以及适用于沸石的陶-埃尔德鲁普模型进行了比较，证明了寿命对孔结构的复杂依赖性。
