Ultrafast Relaxation Dynamics from the S2 State of Malachite Green Studied with Femtosecond Upconversion Spectroscopy

摘要: We have studied the relaxation dynamics in a triphenyl methane (TPM) dye, malachite green (MG), following S2-state excitation using fluorescence up-conversion measurements ethanol and ethylene glycol solutions. Information on mechanisms of radiationless transitions from higher excited states TPM dyes is interesting torsional dynamic aspects phenyl rings for applications involving knowledge excited-state channels. Kinetic at different wavelengths suggested cascade population along S2 state with time constant ∼130 fs that almost independent solvent viscosity two solvents used, contrary to S1 state. Wavelength-dependent time-resolved anisotropy emission bands displayed successive reductions values, indicating continuous evolution surface. A detailed analysis led us propose path...