Vibrational relaxation dynamics

Owrutsky J C, Raftery D and Hochstrasser R M 1994 Vibrational-relaxation dynamics in solutions Ann. Rev. Phys. Chem. 45 519-55... 

To summarize, it has been found that the SH method is able to at least qualitatively describe the complex photoinduced electronic and vibrational relaxation dynamics exhibited by the model problems under consideration. The overall quality of SH calculations is typically somewhat better than the quality of the mean-field trajectory results. In particular, this holds in the case of several curve crossings (see Fig. 2) as well as when the dynamics and the observables of interest are essentially of adiabatic nature— for example, for the calculation of the adiabatic population dynamics associated with a conical intersection (see Figs. 3 and 12). Furthermore, we have briefly discussed various consistency problems of a simple quasi-classical SH description. It has been shown that binned electronic population probabilities and no momentum adjustment for classically forbidden transitions help us to improve this matter. There have been numerous suggestions to further improve the hopping algorithm [70-74] however, the performance of all these variants seems to depend largely on the problem under consideration. 

Finally, solute radical ions can be generated by light-induced, one-photon or multiphoton ionization of their parent compounds (Chaps. 5 and 16). This approach is particularly useful in the ultrafast studies of short-lived, unstable radical ions that aim to unravel their solvation, recombination, reaction, and vibrational relaxation dynamics of the primary charges (see, e.g., Chap. 10). Whereas the time scale of radiolytic production of secondary ions is always limited by the rate with which the primary species reacts with the dispersed parent molecules, light-induced charge separation can occur in <100 fsec. There are many studies on photoionization of solute molecules in liquid solutions we do not intend to review these works. 

The loss of the B state population depends on both the dynamics of the vibrational relaxation and the strength of the coupling of the B state to the repulsive a/a states. In the simulations, the predissociation of the B state molecules is described with the help of the Landau-Zener theory. There, the coupling strength is given by the perturbation energy. Furthermore, the probability for predissociation also depends on the (classical) velocity v t) which relates this process to the vibrational relaxation dynamics of the B state. The theoretical model uses a friction coefficient a to describe the latter process. 

This model is usually called the step-ladder model. According to this model, the vibrational relaxation dynamics of the system depends only on Ay-,0 and vibrational frequency o>. 

Dr. Rohlfing s research interests include the experimental characterization of transient molecules relevant to combustion processes, linear and nonlinear laser spectroscopies, trace detection of pollutants, molecular beam and mass spectrometric studies of carbon and metal clusters, and vibrational relaxation dynamics. He is the author of approximately 50 peer-reviewed articles, holds membership in the American Chemical Society and the American Physical Society, and is a fellow of the American Association for the Advancement of Science. 

Many previous reports [34-44] on the relaxation dynamics of vibrational energy in molecules of a similar size have shown that vibrational energy flows from a solute to solvent molecules on a picosecond time scale, and is completely lost after typically 20 ps in most solutions. This suggests that the vibrational relaxation dynamics in... 

J. C. Owrutsky, D. Raftery and R. M. Hochstrasser, Vibrational relaxation dynamics in solutions,... 

FoggI P, Pettini L, Santa I, Righini R and Califano S 1995 Transient absorption and vibrational relaxation dynamics of the lowest excited singlet state of pyrene in solution J. Phys. Chem. 99 7439-45... 

Li, R Sage, J. T. Champion, P. M., Probing picosecond processes with nanosecond lasers Electronic and vibrational relaxation dynamics of heme proteins. /. Chem. Phys. 1992, 97, 3214-3227. 

Time-resolved anti-Stokes Raman spectroscopy was used for monitoring vibrational relaxation dynamics in solution and provides information about specific modes in molecules under investigation [58, 59]. The experimental setup of a picosecond time-resolved Raman spectrometer is schematically shown in Figure 11.15 [59]. Probe-wavelength dependence of picosecond time-resolved anti-Stokes Raman spectra of a molecule under study allowed determination of... 

In order to discuss various aspects of a MQC treatment of photoinduced electronic and vibrational relaxation dynamics mediated by conical intersections, we consider three different kinds of molecular models, each representing a specific challenge for a MQC modeling. Here, we introduce the specifics of these models and discuss the characteristics of their nonadia-batic dynamics. The molecular parameters of the models are collected in Tables 1-3. 

Dian BC, Florio GM, Clarkson JR, Longarte A, Zwier TS (2004) Infrared-induced conformational isomerization and vibrational relaxation dynamics in melatonin and 5-methoxy-iV-acetyl tryptophan methyl amide. J Chem Phys 120 9033... 

To study the carrier and vibrational relaxation dynamics, mode-locked laser systems, which provide femtosecond pulses and fast and sensitive detection systems are necessary. For detection, streak cameras are used for measurements with time resolution in the subpicosecond range or CCD cameras for time-integrated measurements. For the latter, time resolution can be achieved by using optical Kerr gates or upconversion [266,268]. In general, the two mainly used optical detection mechanisms for coherent phonons (optical, acoustical, or LO-plasmon coupled modes) are the pump/probe [280-285] and the four-... 

From a quantum mechanical perspective, the transient vibrational relaxation dynamics is often studied within a reduced density matrix formalism. The dissipative dynamics of the so-called open system is described by a Liouville von Neumann equation that includes implicitly the effects of the surroundings on the dynamics... 

J. C. Bolinger, T. J. Bixby, and P. J. Reid,/. Chem. Phys., 123,084503 (2005). Time-Resolved Infrared Absorption Studies of the Solvent-Dependent Vibrational Relaxation Dynamics of Chlorine Dioxide. 

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