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Showing papers on "Coupled cluster published in 1974"


Journal ArticleDOI
TL;DR: In this paper, the molecular cluster approach to the problem of small-radius impurity centres in solids is discussed and it is shown that the molecular orbitals obtained for the cluster of host atoms can be connected with the crystalline states only for clusters having the form of a large unit cell.
Abstract: The molecular cluster approach to the problem of small-radius impurity centres in solids is discussed It is shown that the molecular orbitals obtained for the cluster of host atoms can be connected with the crystalline states only for clusters having the form of a large unit cell In this case the molecular orbitals of the cluster have the sense of Wannier functions, the appropriate one-electron energies the sense of mean values of the band energies in the large unit cell scheme of the crystalline state classification It is found that the cluster model is realistic for solids with narrow (1 to 5 eV) energy bands The convergence of the results with increasing cluster size is shown for lithium chloride ([LiCl6]5− [Li14Cl13]+, and [Li18, Cl18]0 are considered), the molecular cluster calculations are performed for some alkali halides and the results are compared with those obtained using band structure calculations [Russian Language Ignored]

19 citations