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C RYSTAL and E MBED , two computational tools for the ab initio study of electronic properties of crystals
Author(s) -
Pisani C.,
Dovesi R.,
Roetti C.,
Causà M.,
Orlando R.,
Casassa S.,
Saunders V. R.
Publication year - 2000
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(2000)77:6<1032::aid-qua9>3.0.co;2-2
Subject(s) - ab initio , variety (cybernetics) , embedding , crystal (programming language) , coulomb , field (mathematics) , computer science , code (set theory) , theoretical physics , statistical physics , chemistry , physics , mathematics , quantum mechanics , artificial intelligence , pure mathematics , set (abstract data type) , programming language , electron
The present study discusses the main features of the two programs C RYSTAL and E MBED developed for the ab initio study of the electronic properties of perfect periodic structures and of crystals with local defects, respectively. After a brief historical introduction, the structure of C RYSTAL is outlined and some specific aspects are discussed in detail: the use of local basis functions, the way of dealing with the Coulomb and the exchange series, the exploitation of point symmetry, the possibility to adopt either the Hartree–Fock approach or one among a variety of Kohn–Sham Hamiltonians. The present capabilities of the program are illustrated by a survey of selected applications from existing literature. Information is provided concerning work in progress aimed at removing some of the limitations of the code and improving its performance. The characteristics of E MBED are analyzed with emphasis given to the critical aspects of the method: limits of validity of the fundamental approximation on which the embedding technique relies, problems of convergence of the self‐consistent procedure; and the delicate issue of the estimate of the defect formation energy. Again, a critical survey of applications clarifies the capabilities of the code. The envisaged improvements to be introduced in a forthcoming release of E MBED are presented. The present and prospective role of the two programs in the field of computational studies of condensed matter problems is outlined. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 1032–1048, 2000