Spectroscopic relaxation processes of rare earth ions in crystals

Abstract Relaxation processes between Stark groups in the (4f) n energy levels of rare-earth salts are discussed. The low temperature spontaneous relaxation rates are exponential in the energy gap to the next lowest Stark group. The rates are determined primarily by the order of the process and the strength of the orbit-lattice interaction. With increasing temperature, stimulated emission of phonons by thermal phonons increases the rate. The presence of molecular groups and 4f n -1 5d bands can cause quite different rates and temperature dependences. Excitation migration to special sites is suggested as a primary mechanism in ion-pair relaxation.

[1]  W. Partlow,et al.  Multiphonon Relaxation in La Cl 3 : Nd 3 + , 1967 .

[2]  L. G. Uitert.  Characterization of Energy Transfer Interactions between Rare Earth Ions , 1967 .

[3]  M. J. Weber,et al.  Radiative and Multiphonon Relaxation of Rare-Earth Ions in Y 2 O 3 , 1968 .

[4]  H. Moos,et al.  MULTIPHONON ORBIT-LATTICE RELAXATION OF EXCITED STATES OF RARE-EARTH IONS IN CRYSTALS. , 1968 .

[5]  G. Dieke,et al.  Ion-Pair Resonance Mechanism of Energy Transfer in Rare Earth Crystal Fluorescence , 1961 .

[6]  R. Birgeneau.  MECHANISMS OF ENERGY TRANSPORT BETWEEN RARE‐EARTH IONS , 1968 .

[7]  D. Paxman,et al.  The visible fluorescence of Er3+ in yttrium gallium garnet , 1966 .

[8]  H. Moos,et al.  EFFECTIVE DENSITY OF PHONON STATES FOR NdCl$sub 3$ FROM VIBRONIC SPECTRA AND APPLICATIONS TO ION-LATTICE INTERACTIONS. , 1968 .

[9]  W. Partlow.  Dynamics of Excited-State Annihilation in NdCl3. , 1968 .

[10]  H. W. Moos,et al.  Rare‐Earth Infrared Lifetimes and Exciton Migration Rates in Trichloride Crystals , 1968 .

[11]  B. Bartolo,et al.  Thermal Dependence of Fluorescence and Lifetimes of Sm2+ in Several Host Lattices , 1967 .

[12]  D. L. Dexter.  A Theory of Sensitized Luminescence in Solids , 1953 .

[13]  H. Moos,et al.  Multiphonon orbit-lattice relaxation in LaBr sub 3, LaCl sub 3, and LaF sub 3. , 1967 .

[14]  R. Orbach.  Spin-lattice relaxation in rare-earth salts , 1961, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[15]  H. Moos,et al.  DIRECT EVIDENCE FOR AND TRANSITION RATES OF ION PAIR INTERACTIONS IN LAC13:HO3+, , 1966 .