Channeling and electromagnetic radiation of relativistic charged particles in metal-organic frameworks
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Channeling and Electromagnetic Radiation of Relativistic Charged Particles in Metal-organic Frameworks1 N. K. Zhevagoa* and V. I. Glebova,b a National b Financial
Research Center “Kurchatov Institute,” Moscow, 123182 Russia University under the Government of Russian Federation, Moscow, 123993 Russia *e-mail: [email protected] Received January 6, 2017
Abstract—We have developed the theory of electromagnetic interaction of relativistic charged particles with metal-organic frameworks (MOFs). The electrostatic potential and electron number density distribution in MOFs were calculated using the most accurate data for the atomic form factors. Peculiarities of axial channeling of fast charged particles and various types of electromagnetic radiation from relativistic particles has been discussed. DOI: 10.1134/S1063776117060176
1. INTRODUCTION The definitive theoretical treatment of channeling of fast charged particles in ordinary crystals was done by Lindhard [1]. Then channeling and associated electromagnetic phenomena were studied in detail both theoretically and experimentally (see, for example, review articles [2–4] and references therein). Channeling is of interest for ion implantation and for highenergy physics in view of the possibility of the deflection of ultra-relativistic particle beams with bent crystals and the generation of intense electromagnetic radiation by fast electrons and positrons. On the other hand, channeling represents the tool for the investigations of crystalline structures themselves. The theory of channeling and associated electromagnetic phenomena was generalized later [5–7] in order to include molecular crystalline structures with nanometer lattice parameters, e.g. nanotubes [5] and fullerites [6], i.e., crystals composed of C60 fullerene molecules. Particularly, it was theoretically predicted that, in contrast with ordinary crystals, in multi-wall carbon nanotubes channeling of thermal neutrons and gamma quanta becomes possible as well. Metal-organic frameworks (MOFs) represent a new class of crystalline hybrid materials with nanometer lattice parameters and wide hollow channels [8]. The crystalline structure of MOFs is much complicated in comparison with the ordinary crystals. The nodes of MOFs are composed of secondary building units (SBUs) of metal oxide ions, joined by organic linkers (such as carboxylates, tetrazolates, sulfonates) through strong covalent bonds. The SBUs and linkers 1 The article is published in the original.
can self-assemble to form 1D chains, 2D sheets and 3D networks. The ease with which the constituents of MOFs can be varied has led to the synthesis of a large number of MOFs have been reported until now [9]. Careful selection of MOF constituents can yield crystals of high thermal and chemical stability. Because of their remarkable physicochemical properties MOFs are usually considered as important materials of possible applications within catalysis, gas adsorption and storage, selective separation, sensing, molecular recognition and cognat
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