Low-Temperature Electron Spectra of Impurities in Naphtalene Crystals

  • N. D. Curmei Institute of Physics, Nat. Acad. of Sci. of Ukraine
  • G. V. Klishevich Institute of Physics, Nat. Acad. of Sci. of Ukraine
  • V. I. Melnyk Institute of Physics, Nat. Acad. of Sci. of Ukraine
Keywords: vibrational structure, absorption and fluorescence spectra, b- and a-naphthalene fluorine, impurity center

Abstract

This work relates to the study of vibrational structures in the electron spectra of naphthalene crystals with impurities of b- and a-naphthalene fluorine with concentrations of 10^−4 to 10 wt.% at a temperature at 4.2 K. It is determined that, at low impurity concentrations, the spectra have a doublet structure and consist of narrow quasilines with initial values of v01 = 31322 cm^−1 and v02 = 31226 cm^−1, which are resonance-coincident in the absorption and fluorescence spectra. It is demonstrated that if the impurity concentration increases, the series of narrow quasilines appear in the areas of the 0-0 transitions of the impurity centers of both types together with the doublet structure. A part of these quasilines is polarized predominantly along the b-axis of a naphthalene crystal. The model is proposed for impurity centers, which induce the generation of new spectral bands. This model is based on the interaction of translation-nonequivalent impurity molecules in the elementary lattice cell of a naphthalene crystal. At high impurity concentrations, the resonance-symmetric wide spectral bands appear in the absorption and fluorescence spectra. The analysis of the results obtained is performed with consideration for the Franck–Condon interaction and the Herzberg–Teller interaction.

References

S.I. Pekar, Research in Electron Theory of Crystals (United States Atomic Energy Commission, Washington, DC, 1963).

A.S. Davydov, ZhETPh 24, 197 (1953).

M.A. Krivoglaz and S.I. Pekar, Trudy Inst. Fiz. AN UkrSSR 4, 37 (1953).

E.V. Shpol’skii, Uspekhi Fiz. Nauk 71, 215 (1960).

M.T. Shpak, Experimental Studies of Luminescense of Molecular Crystals, Doctoral Dissertation (Kiev, 1964) (in Russian).

I.S. Osad’ko, R.I. Personov, and E.V. Shpol’skii, Izv. AN SSSR, Ser. Fiz. 37, 540 (1973).

P.C. Freeman and N.P. Paras, Chem. Phys. Lett. 72, 285 (1980).

N.D. Kurmei, G.V. KLishevich, V.I. Mel’nik, A.G. Tereshchenko, D.I. Zloba, and D. Shcherban, Zh. Prikl. Spektr. 80, 532 (2013).

N.I. Ostapenko, V.I. Sugakov, and M.T. Shpak, Spectroscopy of Defects in Molecular Crystals (Naukova Dumka, Kiev, 1988) (in Russian).

A.I. Kitaigorodskii, Molecular Crystals (Nauka, Moscow, 1971) (in Russian).

Published
2018-10-19
How to Cite
Curmei, N., Klishevich, G., & Melnyk, V. (2018). Low-Temperature Electron Spectra of Impurities in Naphtalene Crystals. Ukrainian Journal of Physics, 59(3), 209. https://doi.org/10.15407/ujpe59.03.0209
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