We demonstrate that the value of the underlying frequency-frequency correlation function can be retrieved from a two-dimensional optical correlation spectrum through a simple relationship. The proposed method yields both intuitive clues and a quantitative measure of the dynamics of the system. The technique is applied to studying the effects of temperature and phase changes on liquid-glass solvent dynamics.
The time and fluence dependence of the homogeneous line width of Zn-porphin in deuterated ethanol glass at 1.8 K is remeasured by stimulated photon echo. The observed spectral dynamics is interpreted in terms of the standard two-level system model and by using a commonly used modified version of it. It is shown, as was suggested recently (Phys. ReV. B 1997, 56, 11571), that time-dependent local heating is the cause of the plateau found in earlier echo experiments on this system. The anomalous intensity loss of the photon echo in the population dimension, however, is confirmed, as well as the existence of excess optical dephasing on a short time scale. The former effect is attributed to spontaneous frequency jumps outside the laser bandwidth, the latter to spectral diffusion induced by the change of electronic state of the chromophore. This phenomenon is not captured in existing theoretical models, which assume the probe molecule to be just a spectator of glass dynamics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.