Effective cross section for scattering from a quasi-stationary state and Einstein relations in the quantum theory of radiation
- Ioffe Physicotechnical Institute, St. Petersburg (Russian Federation)
A theoretical investigation of the correlation between the resonance scattering from a quasi-stationary state and the Einstein relations in the quantum theory of radiation was carried out. On the basis of the Einstein relations, the mode-averaged value of the total scattering cross section at the frequency of the resonance maximum was obtained in the general form. With allowance for radiative, vibronic, transverse, and inhomogeneous widths of a zero-phonon line, relations were obtained that permit the oscillator strength of a resonance electronic transition to be found from measurements of the absorption cross section at the resonance frequency and the half-width of the absorption spectral line. The relations depend on the shape of the absorption spectrum. The cases of the Lorentzian, Gaussian, and Voigt line shapes were considered. Using the E-2A transitions in an optically excited ruby as an example, the cross section of the phonon resonance scattering from impurity centers in crystals with a sufficiently large value of the Debye-Waller factor, e{sup {minus}2M}{ge} 0.5, was considered. The results can be applied in phonon spectroscopy. The main results are interpreted in detail in terms of the Bohr spectroscopic correspondence principle. A new derivation is given of the Ladenburg formula relating the transition probabilities and the dispersion constants. 23 refs., 1 fig.
- OSTI ID:
- 232952
- Journal Information:
- Optics and Spectroscopy, Journal Name: Optics and Spectroscopy Journal Issue: 6 Vol. 79; ISSN OPSUA3; ISSN 0030-400X
- Country of Publication:
- United States
- Language:
- English
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