Relaxation of the 1-2 and 2-3 transitions in ruby
Watts, Roderick Kent
Master of Arts
The interactions by which a System of paramagnetic ions maintains thermal equilibrium with the crystal lattice containing them have been studied experimentally by both non-resonant and resonant methods.12 A resonant pulse method was employed in this investigation because it allows a direct monitoring of the return to equilibrium of a disturbed paramagnetic spin system. The spin system is described by a set of simultaneous rate equations for the populations of the various energy levels of the system. In the pulse method a quantity proportional to the difference between the populations of two energy levels is measured as a function of time. Since solutions of the rate equations are sums of exponentials, the characteristic time constants or relaxation times are the quantities of interest. The relaxation time has been measured for the 1-2 and 2-3 transitions in 0.05% ruby at 9.328 Gc./s. as a function of the angle between a constant magnetic field and the c axis of the crystal at 4.2°K. A pulsed spectrometer was built for making these measurements. Cross relaxation, or spin-spin interaction, was found to be present as well as spin-lattice relaxation.