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Time‐Dependent quantum theory. IV. Effect of lattice relaxation on the optical spectra
Author(s) -
Schurr J. Michael
Publication year - 1971
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.560050208
Subject(s) - diatomic molecule , emission spectrum , chemistry , absorption spectroscopy , spectral line , asymmetry , blueshift , atomic physics , relaxation (psychology) , lattice (music) , molecular physics , molecule , physics , optics , photoluminescence , quantum mechanics , psychology , social psychology , organic chemistry , acoustics
The absorption and emission spectra of a diatomic “molecule” connected to an unstrained linear crystal are calculated for the circumstance where the diatomic undergoes a change of equilibrium internuclear separation in the electronic transition. The expansion (or contraction) of the diatomic results in a frequency dependent line‐width in the customary Lorentzian expression, and is manifested in the absorption spectrum as an asymmetric tailing to the blue, and in the emission spectrum as an asymmetric tailing to the red. The interaction of the diatomic with the lattice also produces a blue‐shift of the absorption spectrum and a red‐shift of the emission spectrum. An important consequence of the asymmetry is the apparent loss of integrated intensity of the line. The striking similarity, both in the width and the over‐all shape, of the emission line calculated here with those observed in the Vegard–Kaplan band of N 2 dissolved in rare gas crystals is discussed.