Premium
Raman and Vibronic Spectra of a New Oxygen Molecule Ion in CaF 2
Author(s) -
Bill H.,
von der Osten W.
Publication year - 1976
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.2220750225
Subject(s) - excited state , raman spectroscopy , overtone , chemistry , vibronic coupling , vibronic spectroscopy , raman scattering , molecular physics , phonon , molecule , ion , spectral line , franck–condon principle , ground state , atomic physics , condensed matter physics , physics , optics , organic chemistry , astronomy
Spectra are reported of an unidentified oxygen molecule center of monoclinic symmetry found in natural crystals of CaF 2 . Two alternative models consisting of a perturbed O 2 −and a O 3 −molecule ion substituting for two fluorine neighbors are discussed. In contrast to the well‐known unperturbed O 2 −center in CaF 2 , this new center has a visible absorption band. This band exhibits vibronic structure corresponding to an excited‐state vibrational frequency of (900 ± 10) cm −1 and coupling constants S ≈ 6 for this vibration and S ≧ 6 for the lattice phonons. This structure is enhanced in stress‐induced dichroism spectra. Resonance Raman scattering excited in this band shows the ground‐state vibrational fundamental at (1038 ± 1) cm −1 and the overtone at (2076 ± 2) cm −1 . The polarization of these features is consistent with the 〈100〉 orientation of the center. The Lorentzian line‐shape, the width, and the relative intensity of the two‐ and one‐phonon scattering peaks are consistent with recent theories of the resonant Raman effect of impurity centers.