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Ground‐state structural and magnetic properties of solid α and β‐O 2
Author(s) -
Etters R. D.,
Helmy A. A.,
Kobashi K.
Publication year - 2009
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.560240854
Subject(s) - condensed matter physics , phonon , sublimation (psychology) , magnetic moment , ground state , translational symmetry , hamiltonian (control theory) , crystal structure , lattice (music) , hexagonal lattice , chemistry , physics , atomic physics , antiferromagnetism , crystallography , psychology , mathematical optimization , mathematics , acoustics , psychotherapist
A pattern recognition optimization scheme coupled with a quasiharmonic lattice dynamics method is used to determine the minimum energy structures and magnetic orientations of solid oxygen. It is shown that the magnetic interaction is responsible for the stability of α‐O 2 with respect to β‐O 2 at zero temperature and pressure. The calculated α‐O 2 lattice parameters, magnetic orientations, and sublimation energy are in good agreement with experiment. Phonon dispersion curves are calculated at k ≠ 0 and the acoustic sound velocities are determined. The rms translational and orientational fluctuations from equilibrium are also calculated. The β‐O 2 phase is described by constraining the magnetic moments so that the magnetic Hamiltonian preserves the hexagonal symmetry of the crystal. The calculated lattice parameters are in good agreement with experiment and a three sublattice, quasihelical magnetic orientation is predicted from structural and energetic considerations.