The study of the influence of Jahn-Teller coupling and low symmetry strain on the anomalous electron paramagnetic resonance spectrum of titanium(III) doped CsAl(SO4)2⋅12H2O

Abstract

The controversial EPR spectrum of titanium(III) as an impurity in cesium aluminum sulphate alum has been re-examined using conventional CW- and a novel pulsed-EPR technique, which monitors the nutation frequency as a function of field. The CW-spectra display a high degree of structure, which is interpreted as arising from chemically distinct titanium(III) species. The two-dimensional nutation spectrum maps the g∥ vs g⊥ relation from just one crystal orientation, and to far greater precision than available from CW-EPR. This novel technique shows that the origin of the linewidths observed for some of the EPR lines is inhomogeneous broadening, the nature of which can be described adequately only in the two-dimensional nutation spectrum. Calculations of g∥ vs g⊥ have been undertaken by numerical diagonalization of the vibronic Hamiltonian. It is found that the relationship between g∥ and g⊥ can be modeled only by assuming that the titanium(III) ions are subject to both dynamic Jahn-Teller coupling and low sym...