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Generalized Internal Strains
Author(s) -
Anastassakis E. M.
Publication year - 1982
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221100118
Subject(s) - internal forces , symmetry (geometry) , strain (injury) , position (finance) , diffraction , crystal (programming language) , matrix (chemical analysis) , physics , phonon , classical mechanics , condensed matter physics , mathematics , optics , materials science , computer science , geometry , structural engineering , engineering , composite material , medicine , finance , economics , programming language
A generalized force (e.g. strain, electric or magnetic field, gradients of forces) applied to a crystal can introduce new atomic position parameters known as internal strains. Each internal strain may be looked as a “frozen” q ≈ 0 optical phonon of appropriate symmetry. Explicit matrix forms can be worked out for each internal strain produced by any type of external force and crystal class. This enables one to determine “selection rules” for deciding the type of force and choice of its components which are necessary to produce an internal strain of given symmetry. Related crystal parameters can be determined in any case with X‐ray diffraction techniques.