Open AccessComparison of the polarizability of periodic systems computed by using the length and velocity operators
Author(s) -
Michel Rérat,
M Ferrero,
E. Amzallag,
Isabelle Baraille,
Roberto Dovesi
Publication year - 2008
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/117/1/012023
Subject(s) - basis (linear algebra) , polarizability , rotation formalisms in three dimensions , gaussian , basis set , set (abstract data type) , dielectric , mathematics , code (set theory) , diamond , constant (computer programming) , computational chemistry , statistical physics , mathematical analysis , physics , materials science , chemistry , quantum mechanics , geometry , computer science , molecule , density functional theory , composite material , programming language
International audienceThe theorem relating the length (L) and velocity (V) operators, that permits to compute in two alternative ways the polarizabilities of finite systems, is generalized to periodic infinite cases. The two alternative strategies have been implemented in the CRYSTAL code, that uses Gaussian type basis sets, within the CPHF and CPKS formalisms. The dielec. const. of diamond, SiC, silicon and MgO has been obtained with four different hamiltonians (HF, LDA, PBE, B3LYP). The effect of basis set and other computational parameters are discussed. It turns out that when a relatively extended basis set is used, LDA and PBE results obtained with the L and V operators nearly coincide, whereas HF and B3LYP schemes provide different results, as expected on the basis of the non-commutability of the HF-exchange and length operators. [on SciFinder(R)