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Density matrix of crystalline systems. II. The influence of structural and computational parameters
Author(s) -
Pisani C.,
Aprà E.,
Causà M.,
Orlando R.
Publication year - 1990
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/qua.560380305
Subject(s) - chemistry , boron nitride , basis set , density matrix , beryllium , hamiltonian (control theory) , linear combination of atomic orbitals , computational chemistry , basis (linear algebra) , electron density , condensed matter physics , molecular physics , density functional theory , electron , quantum mechanics , physics , mathematics , quantum , mathematical optimization , geometry , organic chemistry
The one‐electron density matrix ( DM ) of a number of crystalline systems—lithium, graphite, boron nitride, silicon, and beryllium—are considered here, as resulting from Hartree–Fock– SCF‐LCAO calculations. The influence of structural and computational parameters is discussed. It is shown in particular why the structure of chemical bonds in semiconductors leads to an oscillating long‐range behavior of the DM , similar to that observed in metals, where these oscillations are related to the very existence of a Fermi surface. Concerning computational parameters, the influence of the density of sampling k points and of basis set on the calculated DM is considered; it is shown that the choice of the basis set is not a very critical one as far as the DM range is concerned. Some critical aspects of the interrelation between DM range and exchange part of the Fock Hamiltonian are analyzed.