PHOTOEQUILIBRIUM BETWEEN KCl F AND F CENTERS AT 80 K

Journal Article · Tue May 15 04:00:00 EDT 1962 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.126.1410· OSTI ID:4838603

Costikas, A; Grossweiner, L I

The illumination of F centers in KCl at 80 deg K establishes a photoequilibrium between F' and F centers. The equilibrium transformations are reversible and are of the same magnitude for additively colored crystals and crystals x-rayed at 80 deg K and 300 deg K. The photostationary ratio of F' to F centers varies with the logarithm of the incident light intensity. Transitions between equilibrium levels approximate firstorder processes, controlled by the rate of light absorption in the F and F- bands. A kinetic model is proposed in which the elementary steps are the photoionization of F and F' centers, and electron capture at F centers and negative-ion vacancies. The variation of light intensity and spectrum through the crystal is accounted for by assuming that temporal equilibrium is maintained in local regions and integrating the results over the crystal volume. The photoionization quantum efficiency of the F center at 80 deg K is calculated to be 0.020 plus or minus 0.003; this quantity is one- half of the photobleaching quantum efficiency. A value of 0.016 plus or minus 0.005 is obtained for the ratio of the electroncapture cross section of the F center to the chloride-ion vacancy. (auth)

• Research Organization: Illinois Inst. of Tech., Chicago
• NSA Number: NSA-16-021193
• OSTI ID: 4838603
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 126; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
CAPTURE
COLOR
CRYSTALS
DEFECTS
EFFICIENCY
ELECTRONS
ENERGY LEVELS
F CENTERS
IONIZATION
IONS
IRRADIATION
LATTICES
LIGHT
LOW TEMPERATURE
NUMERICALS
PHOTONS
PHYSICS
POTASSIUM CHLORIDES
SPECTRA
STABILITY
TRANSIENTS
VACANCIES
X RADIATION