Intensity and bandwidth of multiphonon vibronic transitions of rare earth ions in crystals.

Journal Article · Thu Apr 10 04:00:00 EDT 2003 · Mol. Phys.

DOI:https://doi.org/10.1080/0026897021000046889· OSTI ID:961089

Liu, G K; Chen, X Y; Huang, J

The theory of multiphonon vibronic coupling to electronic transitions is applied in analysing fluorescence spectra of Eu{sup 2+} in BaFCl, which consist of the 4f{sup 7} ({sup 6}P{sub 7/2}) {yields} 4f{sup 7} ({sup 8}S{sub 7/2}) and 4f{sup 6}5d {yields} 4f{sup 7} transitions, and the 4f{sup 7}-4f{sup 6}5d excitation spectrum of Ce{sup 3+} in YPO{sub 4}.. The 4f electrons are weakly coupled to lattice vibration modes so that only weak one- and two-phonon sidebands are observable in the 4f-4f optical transitions, whereas the electron-phonon coupling is significantly stronger for a 5d electron. Accordingly, intensive multiphonon vibronic transitions overwhelmingly dominate the 4f{sup 6}5d {yields} 4f{sup 7} spectrum. It is shown that the extended Judd-Ofelt theory for weak vibronic coupling in the framework of the M-process is equivalent to the Huang-Rhys theory for the {Delta}-process. In the analysis of experimental data, contributions from local ligand modes and lattice acoustic modes are separated, and the coupling strength is evaluated, in terms of the Huang-Rhys parameter S, for the 4f-4f and 5d-4f vibronic transitions.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 961089
• Report Number(s): ANL/CHM/JA-44548
• Journal Information: Mol. Phys., Journal Name: Mol. Phys. Journal Issue: 7 ; Apr. 10, 2003 Vol. 101; ISSN MOPHAM; ISSN 0026-8976
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ACOUSTICS
COUPLING
CRYSTALS
ELECTRON-PHONON COUPLING
ELECTRONS
EXCITATION
FLUORESCENCE
IONS
LATTICE VIBRATIONS
LIGANDS
RARE EARTHS
SPECTRA