Femtosecond studies of twisting dynamics of auramine in solution

✍ Scribed by M. Glasbeek; H. Zhang; M.J. van der Meer

• Book ID: 104304096
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 247 KB
• Volume: 86
• Category: Article
• ISSN: 0167-7322
• DOI: 10.1016/s0167-7322(99)00133-6

✦ Synopsis

Femtosecond fluorescence upconversion experiments as performed for photoexcited auramine (a diphenylaminemethane dye) in liquid solution are discussed. Upon pulsed laser excitation the solute shows a dynamic Stokes shift as well as a drop in fluorescence intensity in only a few picoseconds. From a study of the excited state dynamics as a function of solvent viscosity it is concluded that auramine undergoes a picosecond (quasi)-barrierless relaxation from an emissive state to a non-emissive excited state that decays to the ground state in about 30 ps. The relaxation is controlled by the torsional motions of the phenyl rings of the auramine molecule.