Photon echo experiments on diethylthiacarbocyanine iodide (DTCI) in dibuthylphthalate (DBP) and glycerol in the glass phase with femtosecond pulses are presented. The PE signal shows nonexponential decays even at low temperatures. This behavior is attributed to the many vibronic resonances of the chromophore/ glass system which can be simultaneously excited by the spectral bandwith of the laser pulses. We are able to extract from the PE decays the contribution of the homogeneous dephasing rate of the 0-0 transition of DTCI up to 20K in dibutylphthalate and 40 K in glycerol. A beating structure in the echo decay for the system DTCI/DBP is also observed from 8 K up to 180 K (glass transition temperature for DBP). This feature is attributed to an intereference process involving excitation of a vibronic transition of DTCI characterized by a vibrational frequency of 300 cm(-1).
Photon echo experiments on 3-3 ' diethylthiacarbocyanine in glass-forming liquids with ultrafast laser pulses
FERRANTE, CAMILLA
1998
Abstract
Photon echo experiments on diethylthiacarbocyanine iodide (DTCI) in dibuthylphthalate (DBP) and glycerol in the glass phase with femtosecond pulses are presented. The PE signal shows nonexponential decays even at low temperatures. This behavior is attributed to the many vibronic resonances of the chromophore/ glass system which can be simultaneously excited by the spectral bandwith of the laser pulses. We are able to extract from the PE decays the contribution of the homogeneous dephasing rate of the 0-0 transition of DTCI up to 20K in dibutylphthalate and 40 K in glycerol. A beating structure in the echo decay for the system DTCI/DBP is also observed from 8 K up to 180 K (glass transition temperature for DBP). This feature is attributed to an intereference process involving excitation of a vibronic transition of DTCI characterized by a vibrational frequency of 300 cm(-1).Pubblicazioni consigliate
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