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Spectroscopic investigation of orientational disorder in an acenaphthylene molecular crystal
Author(s) -
Korets A. Ya.,
Fedorov V. P.,
Korshunov A. V.,
Naumov V. A.
Publication year - 1977
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.2220840112
Subject(s) - acenaphthylene , singlet state , exciton , crystal (programming language) , molecule , resonance (particle physics) , spectral line , absorption (acoustics) , molecular physics , intensity (physics) , materials science , atomic physics , condensed matter physics , chemistry , physics , optics , excited state , phenanthrene , organic chemistry , computer science , programming language , astronomy , environmental chemistry
The electronic absorption spectra of an acenaphthylene single crystal are obtained in polarized light at 4.2 to 300 K. The temperature dependence of band width, maximum and integral intensity of the lowest singlet‐singlet transition at v = 21762 cm −1 are discussed. Both the band broadening of the exciton doublet with v a = 21260 cm −1 and v b = 21280 cm −1 and its intensity decrease are shown to be due to a change of orientational disorder, when approaching the orientational phase transition at T = 130 K. The constancy of Davydov splitting Δ = 20 cm −1 with temperature is associated with inter‐ordering of two sets of translationally non‐equivalent acenaphthylene molecules, which does not influence the value of resonance interaction between the pair molecules.