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Theoretical Study of Structural and Electronic Properties of Sodium in Zeolitic Cage
Author(s) -
Sun Qiang,
Ye Ling,
Xie Xide
Publication year - 1998
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199806)207:2<357::aid-pssb357>3.0.co;2-c
Subject(s) - cage , chemistry , cluster (spacecraft) , atom (system on chip) , adsorption , zeolite , ionization , crystallography , coulomb , electronic structure , sodium , metal , fermi level , atomic physics , ionization energy , molecular physics , chemical physics , computational chemistry , ion , electron , physics , mathematics , organic chemistry , computer science , embedded system , programming language , catalysis , biochemistry , combinatorics , quantum mechanics
The structural and electronic properties of sodium adsorbed in the β‐cage of zeolite A have been studied by using the extended Hckel method and cluster model. The β‐cage, which consists of Si 12 Al 12 O 48 , is one of the structural units of zeolite A. The site preference for a Na adatom and several stable configurations for Na adatoms in the β‐cage have been determined and the electronic structures of the systems are investigated. It is found that instead of forming metal clusters the Na adatoms prefer to be adsorbed separately at adsorption sites I or II which are located near the center of the hexagonal face (site I) and on the square face (site II) in the β‐cage, respectively. The result is reasonable from the fact that the adsorbed Na atoms are almost ionized so that the Coulomb repulsion prevents them from forming clusters at short distances. The electronic structures show that the peak near the Fermi level increases obviously after the incorporation of sodium atoms into the β‐cage. A new peak which is near the first ionization energy (5.14 eV) of Na atom appears when the numbers of Na atoms adsorbed by the β‐cage are larger than twelve.