AbstractsPhysics

The paramagnetic resonance spectrum of the rare Ti3+ ion in cubic RbAl(SO4)2. 12H20 has been investigated with an X-band microwave spectrometer at liquid helium temperatures. Spectra were plotted for the d-c magnetic field rotated in the {100} and {011} planes and twelve resonance lines were observed. By considering a model of twelve magnetic complexes, three different g-factors have been determined, 1.895 +/- .002, 1.715 +/- .002 and 1.767 +/- .002, which result from a crystal electric field of orthorhombic symmetry. Through the application of group theory and quantum mechanical perturbation methods, crystal field energy levels have been calculated to be 1050 cm.-1, 1320 cm.-1 and 20,300 cm.-1 above the ground state, with the last value fitting the result of an optical spectroscopic experiment with Ti3+ in a similar environment. Spin-lattice relaxation measurements were made between 4. 2 °K and 1.6 °K and the relaxation time T1 was found to vary from 3. 3 msec. to 63 msec. over this temperature range. From the nature of the temperature dependence, it is evident that the Raman process is dominant at 4.2°K, as theoretical calculations have predicted. The concentration of titanium substituted for aluminum in the crystals studied has been estimated to be 0.02 per cent.