The photoexcited triplet state of a 4-4'-disubstituted dithiophene has been investigated by time-resolved ESR in two different solid matrixes-glassy toluene which acts as an amorphous isotropic medium and a spirocyclophosphazene host compd.-which provides an ordered confining structure to guest mols. Different spectral line shapes with different temp. dependence have been obtained using continuous-wave or spin-echo detection. This behavior was attributed to spin relaxation due to modulation of the zero-field splitting tensor induced by fast librational motion of the dithiophene triplet. Moreover, differences between line shapes in the two matrixes were reproduced considering a librational motion occurring preferentially around different mol. axes
Barbon, A., Bortolus, M., Brustolon, M., Comotti, A., Maniero, A., Segre, U., et al. (2003). Dynamics of the Triplet State of a Dithiophene in Different Solid Matrixes Studied by Transient and Pulse EPR Techniques. JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL, 107(14), 3325-3331 [10.1021/jp026214f].
Dynamics of the Triplet State of a Dithiophene in Different Solid Matrixes Studied by Transient and Pulse EPR Techniques
COMOTTI, ANGIOLINA;SOZZANI, PIERO ERNESTO
2003
Abstract
The photoexcited triplet state of a 4-4'-disubstituted dithiophene has been investigated by time-resolved ESR in two different solid matrixes-glassy toluene which acts as an amorphous isotropic medium and a spirocyclophosphazene host compd.-which provides an ordered confining structure to guest mols. Different spectral line shapes with different temp. dependence have been obtained using continuous-wave or spin-echo detection. This behavior was attributed to spin relaxation due to modulation of the zero-field splitting tensor induced by fast librational motion of the dithiophene triplet. Moreover, differences between line shapes in the two matrixes were reproduced considering a librational motion occurring preferentially around different mol. axes
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