Real-time dynamics

Rosker M J, Rose T S and Zewail A 1988 Femtosecond real-time dynamics of photofragment-trapping resonances on dissociative potential-energy surfaces Ghem. Phys. Lett. 146 175-9... 

T. Sinhora and S. Kasada, "A Real Time Dynamic Simulator for the Residue ECC Process," paper presented at Eastern Simulation Conference, Odando, Fla., Apr. 18-21,1988. 

As long as the system can be described by the rate constant - this rules out the localization as well as the coherent tunneling case - it can with a reasonable accuracy be considered in the imaginary-time framework. For this reason we rely on the Im F approach in the main part of this section. In a separate subsection the TLS real-time dynamics is analyzed, however on a simpler but less rigorous basis of the Heisenberg equations of motion. A systematic and exhaustive discussion of this problem may be found in the review [Leggett et al. 1987]. 

A successful method to obtain dynamical information from computer simulations of quantum systems has recently been proposed by Gubernatis and coworkers [167-169]. It uses concepts from probability theory and Bayesian logic to solve the analytic continuation problem in order to obtain real-time dynamical information from imaginary-time computer simulation data. The method has become known under the name maximum entropy (MaxEnt), and has a wide range of applications in other fields apart from physics. Here we review some of the main ideas of this method and an application [175] to the model fluid described in the previous section. 

M. A. Acra, and J. D. Goeschl, Carbon partitioning patterns of mycorrhizal versus non-mycorrhizal plants real-time dynamic measurements using "CO2, New Phyiol. //2 489 (1989). 

Figure 5.13. In situ atomic-resolution ETEM image of Pt/titania catalyst (a) finely dispersed Pt particles (b) in situ real-time dynamic activation in hydrogen imaged at 300 C. The 0.23 nm (111) atomic lattice spacings are clearly resolved in the Pt metal particle, P and (c) the same particle imaged at 450 C, also in H2. SMSI deactivation with a growth of a Ti-oxide overlayer (C), and the development of nanoscale single-crystal clusters of Pt, with atomic resolution (arrowed). (After Gai 1998.)...

Williams, S.O. and Imre, D.G. (1988c). Determination of real time dynamics in molecules by femtosecond laser excitation, J. Phys. Chem. 92, 6648-6654. 

Like PELDOR FRET requires labeling with two labels. Commonly, these labels are smaller for PELDOR and PELDOR does not need two different labels for high-quality data. Yet, FRET can be performed on the single molecule level, in liquid solution, and provides real-time dynamics... 

Note also that the form of the pulse does not appear in the expression [Eq. (2.78)] for the cross section. This is because resolving the energy, embodied in the orthogonality expression [Eq. (2.47)], extracts a single frequency component of e(to), whose contribution is canceled in the division by the incident light intensity. Therefore, as shown in Appendix 2A, we can use any convenient pulse shape to compute energy-resolved quantities. This is not the case if we want to follow the real-time dynamics of the system, where the pulse shape is intimately linked with the observables. Indeed this link prevents a pulse-free definition of concepts such as the lifetime of a state. This issue is addressed in Appendix 2A. 

Kang H, Lee KT, Kim SK (2002) Femtosecond real time dynamics of hydrogen bond dissociation in photoexcited adenine-water clusters. Chemical Physics Letters 359 213-219. 

Although dynamic responses of microbial systems are poorly understood, models with some basic features and some empirical features have been found to correlate with actual data fairly well. Real fermentations take days to run, but many variables can be tried in a few minutes using computer simulation. Optimization of fermentation with models and real-time dynamic control is in its early infancy however, bases for such work are advancing steadily. The foundations for all such studies are accurate material balances. 

Following the above-mentioned spectroscopic study by Johnson and co-workers [55], Neumark and co-workers [56] explored the ultrafast real-time dynamics that occur after excitation into the CTTS precursor states of I (water) [n — 4-6) by applying a recently developed novel method with ultimate time resolution, i.e., femtosecond photoelectron spectroscopy (FPES). In anion FPES, a size-selected anion is electronically excited with a femtosecond laser pulse (the pump), and a second femtosecond laser pulse (the probe) induces photodetachment of the excess electron, the kinetic energy of which is determined. The time-ordered series of the resultant PE spectra represents the time evolution of the anion excited state projected on to the neutral ground state. In the study of 1 -(water), 263 nm (4.71 eV) and 790 nm (1.57 eV) pulses of 100 fs duration were used as pump and probe pulses, respectively. The pump pulse is resonant with the CTTS bands for all the clusters examined. 

In this chapter we focus on the real-time dynamics of IVR, with particular... 

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