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Thermal Broadening and Shift of the Zero‐Phonon Lines in Optical Spectra of Impurity Organic Crystals
Author(s) -
Sapozhnikov M. N.
Publication year - 1971
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.2220460208
Subject(s) - phonon , impurity , debye model , adiabatic process , condensed matter physics , spectral line , adiabatic theorem , line (geometry) , debye , materials science , atomic physics , physics , quantum mechanics , geometry , mathematics
A theoretical interpretation is made of all the data on the temperature broadening and shift of the zero‐phonon lines in spectra of impurity normal paraffin crystals. It is shown that the broadening of most lines investigated may be well described in the Debye approximation using the theoretical dependence, obtained on the basis of the Krivoglaz‐McCumber model in which adiabatic, Condon and harmonic approximations were utilized, and a small change of the elastic constants of the lattice vibrations and a displacement of the equilibrium positions of nuclei induced by the electron transition in the impurity centre were taken into account. The line shifts could not be described by the theoretical formula obtained in the same approximation. The possible reasons of this discrepancy are discussed.