Anomalous lineshapes and aging effects in two-dimensional correlation spectroscopy.
Multitime correlation functions provide useful probes for the ensembles of trajectories underlying the stochastic dynamics of complex systems. These can be obtained by measuring their optical response to sequences of ultrashort optical pulse. Using the continuous time random walk model for spectral diffusion, we analyze the signatures of anomalous relaxation in two-dimensional four wave mixing signals. Different models which share the same two point joint probability distribution show markedly different lineshapes and may be distinguished. Aging random walks corresponding to waiting time distributions with diverging first moment show dependence of 2D lineshapes on initial observation time, which persist for long times.
Sanda
Frantisek
F
Faculty of Mathematics and Physics, Institute of Physics, Charles University, Ke Karlovu 5, Prague 121 16, Czech Republic. sanda@karlov.mff.cuni.cz
Mukamel
Shaul
S
D000465:Algorithms; D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D004058:Diffusion; D008390:Markov Chains; D015233:Models, Statistical; D008968:Molecular Conformation; D016011:Normal Distribution; D011336:Probability; D013057:Spectrum Analysis / Q000379:methods*; D013269:Stochastic Processes; D013997:Time Factors