Jahn-Teller coupling in the excited level of the F+ centre in CaO: uniaxial stress effect

Linear dichroism has been measured in both the absorption and emission bands of the F+ centre in CaO under uniaxial stress. In order to analyse the emission results the method of moments is generalized to transitions taking place from an orbitally degenerate level. It is shown that this analysis allows a direct determination of the Ham reduction factors. It is verified that absorption and emission measurements lead to the same values for these factors K(E)=0.40, K(T2)=0.39. These values when compared with K(T1)=0.02 clearly show that the excited level is subject to the special kind of Jahn-Teller effect described by O'Brien (1971). Detailed analysis of the polarized spectra allows the determination of the symmetry of the modes of vibration giving rise to the vibronic structure and clearly shows that modes in a large range of energies are involved in the Jahn-Teller coupling.

[1]  A. Hughes,et al.  Symmetry assignments of one-phonon sidebands in the emission spectrum of the F+ centre in calcium oxide , 1972 .

[2]  P. R. Son,et al.  CaO and SrO single crystal elastic constants and their pressure derivatives , 1972 .

[3]  R. Romestain,et al.  Jahn-Teller Effect of an Orbital Triplet Coupled to Both E g and T 2 g Modes of Vibrations: Symmetry of the Vibronic States , 1971 .

[4]  M. O'brien,et al.  The Jahn-Teller effect in a p state equally coupled to Eg and T2g vibrations , 1971 .

[5]  A. Hughes,et al.  Vibronic properties of the F + absorption band in calcium oxide , 1971 .

[6]  G. Peckham,et al.  The lattice dynamics of calcium oxide , 1971 .

[7]  W. Hayes,et al.  Stark effect of the F+ centre in CaO , 1971 .

[8]  A. Roussel,et al.  Magneto-Optic Study of the Jahn-Teller Effect in the Excited Level of theF+Centers in CaO , 1971 .

[9]  B. Evans,et al.  Vibronic Aspects of the CaO and MgOFBands , 1970 .

[10]  A. Hughes.  A solution of the calcium oxide F+ centre problem using a two mode Jahn-Teller effect) , 1970 .

[11]  Mary C. M. O'Brien,et al.  Dynamic Jahn-Teller Effect in an Orbital Triplet State Coupled to Both E g and T 2σ Vibrations , 1969 .

[12]  B. Henderson,et al.  Luminescence fromFCenters in Calcium Oxide , 1969 .

[13]  S. Jasperson,et al.  An improved method for high reflectivity ellipsometry based on a new polarization modulation technique [Rev. Sci. Instrum. 40, 95 (1969)] (Errata) , 1969 .

[14]  A. Hughes,et al.  Stress and Zeeman spectra in bismuth-doped and undoped calcium oxide , 1969 .

[15]  P. Duval,et al.  Dichroïsme circulaire des centres R dans KCl , 1968 .

[16]  B. Evans,et al.  F-center emission and the 3557-Å zero-phonon line in CaO☆ , 1968 .

[17]  J. C. Kemp,et al.  Faraday Rotation of the CaOFBand and 3557 Å Zero-Phonon Peak , 1968 .

[18]  J. Gareyte,et al.  Effet zeeman des centres r dans KC1 , 1966 .

[19]  S. Schnatterly.  The Effect of Applied Uniaxial Stresses on The Optical Absorption of F-Centers in Alkali-Halides , 1965 .

[20]  F. Ham.  Dynamical Jahn-Teller Effect in Paramagnetic Resonance Spectra: Orbital Reduction Factors and Partial Quenching of Spin-Orbit Interaction , 1965 .

[21]  R. H. Silsbee.  R CENTER IN KCl STRESS EFFECTS IN OPTICAL ABSORPTION , 1965 .

[22]  R. Loudon.  Selection rules for defect-activated lattice bands and vibronic transitions in face-centred cubic, diamond and zinc blende lattices , 1964 .

[23]  C. Henry,et al.  EFFECT OF APPLIED FIELDS ON THE OPTICAL PROPERTIES OF COLOR CENTERS , 1964 .