In:
The Journal of Chemical Physics, AIP Publishing, Vol. 93, No. 5 ( 1990-09-01), p. 3101-3110
Abstract:
An electron paramagnetic resonance (EPR) study with laser flash excitation and electron-spin-echo detection is reported on the very weakly luminescent state of the CrO2−4 ion in an anhydrite (CaSO4) host. On excitation a lowering of symmetry of the chromate ion occurs, and four sets of congruent excited species are observed, interrelated by the orthorhombic symmetry of the crystal. The results can be fitted to a spin Hamiltonian for an orbitally nondegenerate triplet state with parameters D=−20.337 GHz, E=−0.211 GHz, g11=1.961, g22= 1.989, and g33=1.9817. The relaxation behavior of the triplet state has been studied by varying (1) the delay between the laser flash and the first microwave pulse and (2) the interval τ between the microwave pulses. The lifetimes of the zero-field spin states are τx=2.2, τy=0.73, and τz=0.023 μs. Because of the very fast decay of the Tz level and attendant very short relaxation time T2 for most orientations of the magnetic field, the four ‘‘allowed’’ stationary EPR transitions in our X-band experiment could only be observed by using a stripline cavity and reducing τ to less than 100 ns.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
1990
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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