THE INTERACTION OF PARAMAGNETIC IONS WITH LATTICE VIBRATIONS
Abstract
The theory of the interaction of a paramagnetic ion with the lattice vibrations in an ionic crystal is investigated. A generalization of the Van Vleck approach to spin-lattice relaxation is developed which allows the determination of the effective vibrating crystal field in a semiempirical manner. This technique is an improvement over some previous estimates of the vibrating potentials. The theory of relaxation effects in excited states of ionic crystals is presented in some detail. In addition to the conventional single phonon relaxation process, the theory of multi-phonon emission is developed as a tentative explanation of the quenching of fluorescence observed in many paramagnetic crystals. The simple (one phonon) relaxation theory is applied to the case of the 2E state of ruby. A variety of states in rare earth crystals are also investigated on the basis of the simple relaxation theory. Another mechanism for the temperature dependence of the line breadth is developed which is based on the adiabtic variation of the local fields due to lattice vibrations. The adiabatic and relaxation line broadening mechanisms are compared for the rare earths. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1962
- Accession Number
- AD0275763
Entities
People
- A. Kiel
Organizations
- Johns Hopkins University