Determination of the dynamics of microcharacteristics of solutions by time laser spectroscopy

Abstract

The development of simple methods used to analyze the available data and separate the contributions from the main physicochemical processes responsible for the kinetics of instantaneous emission spectra is of considerable interest due to the intensive investigation of the time-resolved characteristics of fluorescence of various quantum objects that are used to examine the most important photophysical and photochemical reactions in excited states. The relation between the functions of the shift in the instantaneous spectra of spontaneous emission of molecules (obtained using kinetic spectroscopy methods) and the time variations in the configurational structure of solvates, as well as the charge transfer in the excited singlet state of molecules of the luminescent probe, has been shown using simple analytical expressions of solvatofluorochromism. The fluorescence of solutions of one of the most important molecular probes, namely, 1-(phenylamino)naphthalene in glycerol, has been investigated with a picosecond time resolution. This molecular probe is known because its electric dipole moment is formed in the excited singlet state, which almost instantaneously initiates processes of intermolecular rearrangement of solvent molecules. It has been demonstrated that it is possible to determine the time dependence of the function of the dielectric response of the polar solvent to the dipole of this probe and, hence, the time evolution of the microcharacteristics of the solvent that determine the above function.