L'ion positif géminé intervient-il sur le destin de l'électron piégé incomplètement relaxé dans les liquides polaires irradiés?

1992 ◽  
Vol 70 (6) ◽  
pp. 1869-1871
Author(s):  
J.-P. Jay-Gerin ◽  
C. Ferradini
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Coulomb Field ◽  
Early Time ◽  
Localized States ◽  
Polar Liquids ◽  
Time Dynamics ◽  
Electron Solvation ◽  
Trapped Electron ◽  
Positive Ion

A model is proposed concerning the influence of the parent positive ion on the fate of the incompletely relaxed trapped electron (eir−) in irradiated polar liquids. This model is based on the release, by a tunneling and (or) a trap-hopping mechanism in the Coulomb field of the cation, of the electrons captured in preexisting shallow localized states below the bottom of the conduction band of the solvent. The released electrons would either recombine with the parent positive ion or get retrapped. The net effect would be an accumulation of electrons in deeper traps. The removal of weakly trapped electrons would contribute to the decrease of the infrared part of the optical absorption spectrum during the very early time dynamics of electron solvation. Such a process would imply, as a consequence, the existence of a maximum of the eir− absorption spectrum.

An investigation of the effects of X-rays on undoped and on hydrogen doped alkaline earth fluorides

1969 ◽  
Vol 309 (1496) ◽  
pp. 69-90 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Optical Absorption Spectrum ◽  
Alkaline Earth ◽  
Room Temperature ◽  
X Rays ◽  
Hydrogen Atoms ◽  
X Irradiation ◽  
Trapped Electron ◽  
Extract Information

We have investigated, using e.p.r. methods, the effects of X-rays on undoped and hydrogendoped alkaline earth fluorides. We find that irradiation of undoped CaF 2 at any temperature does not produce F centres in observable concentration. Irradiation of undoped SrF 2 and BaF 2 at 77 °K produces V k centres and trapped electron centres which anneal out below room temperature. The undoped SrF 2 and BaF 2 crystals are extremely difficult to colour with room temperature X-irradiation due, apparently, to recombination of electrons and holes. Irradiation of SrF 2 :H and BaF 2 :H crystals at 77 °K produces hydrogen atoms in fluorine sites (Hg centres) and trapped electron centres. The rate of introduction of the electron centres into the crystals is greater by a factor of about 3 than in the undoped crystals. Irradiation of CaF 2 :H at 77 °K also produces Hg centres and trapped electron centres but the rate of generation of the electron centres in these crystals is greater than in undoped CaF 2 by a factor of at least 25. The origin of this difference in the behaviour of CaF 2 :H and the behaviour of SrF 2 :H and BaF 2 :H and the nature of the response of alkaline earth fluorides to X-rays are discussed. The use of polarized bleaching light to extract information from the optical absorption spectrum of irradiated CaF 2 :H is described in an appendix.

Early-time dynamics of wave fronts in disordered triangular lattices

1998 ◽  
Vol 57 (2) ◽  
pp. R1255-R1258 ◽  
Author(s):  
M. Kellomäki ◽  
J. Åström ◽  
J. Timonen
Keyword(s):  
Early Time ◽  
Wave Fronts ◽  
Time Dynamics ◽  
Triangular Lattices
Sign in / Sign up

Export Citation Format

Share Document