dc.creator Bloor, D. en_US dc.creator Ellis, E. en_US dc.creator Martin, D. H. en_US dc.creator Wadham, A. en_US dc.date.accessioned 2006-06-15T16:42:08Z dc.date.available 2006-06-15T16:42:08Z dc.date.issued 1967 en_US dc.identifier 1967-W-3 en_US dc.identifier.uri http://hdl.handle.net/1811/15381 dc.description Author Institution: Department of Physics, Queen Mary College en_US dc.description.abstract The low lying electronic levels of rare earth ions, produced by crystal field splitting of the degenerate groundstate, have been observed in the absorption spectra of some rare earth double nitrates, ethyl sulphates and oxides. In the spectral range $10-50 cm^{-1}$ at least one absorption occurs clear of obscuring lattice absorption bands. Use of coolded InSb phtoconductive detectors, together with a simple grating monochromator, allows a resolution of $0.1 cm^{-1}$ to be obtained. The spectra give accurate values for line positions, widths and strengths. Line positions agree with values obtained by optical, ESR, specific heat and susceptibility measurements. Theoretical estimates of absorption strengths for magnetic dipole transitions are in reasonable accord with the experimental values. The linewidths in concentrated compounds are somewhat greater than values predicted from previous spin lattice relaxation measurements. Samples made by diluting the paramagnetic ions in the lanthanum compounds show a concentration dependent linewidth indicating that ion-ion- interactions are important. Theoretical estimates indicate that the two most important factors determining linewidth are the direct spin-lattice relaxation and a non dipoler ion-ion interaction (either electric quadrupolar or virtual phonon). Present address of E. Ellis: University of York. en_US dc.format.extent 169726 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title FAR INFRARED SPECTRA OF SOME RARE EARTH COMPOUNDS. en_US dc.type article en_US
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