Controlled reactions, vibrational

THEORY OF LASER CONTROL OF VIBRATIONAL TRANSITIONS AND CHEMICAL REACTIONS BY ULTRASHORT INFRARED LASER PULSES... 

At the microscopic level, chemical reactions are dynamical phenomena in which nonlinear vibrational motions are strongly coupled with each other. Therefore, deterministic chaos in dynamical systems plays a crucial role in understanding chemical reactions. In particular, the dynamical origin of statistical behavior and the possibility of controlling reactions require analyses of chaotic behavior in multidimensional phase space. 

Several solvent induced relaxation processes are involved in this process Diffusion, trapping, geminate recombination, and vibrational relaxation. In addition, the A X transition represents the important class of nonadiabatic reactions, here induced by the solute-solvent interaction. Furthermore, the interaction between the molecular species and the radiation field, used to initiate and to monitor the process, is modified by the solvent environment. Other important solvent induced processes Diffusion controlled reactions, charge (electron, proton)... 

Figure 1. Time dependence of elementary chemical processes in solutions. In polar solutions, most of these primary events (electron detachment, ion-ion pair inter-conversion, concerted electron-proton transfer, and electron solvation) occur in less than 2 X 1Q s and are controlled by vibrational or electronic responses of the reaction medium.

However, at that time there still existed a healthy scepticism regarding the existence of nonperiodic behaviour in well-controlled reactions. After all, nonperiodic behaviour can arise from fluctuations in stirring rate or flow rate, evolution of gas bubbles from the reaction, spatial inhomogeneities due to incomplete mixing, vibrations in the stirring motor, fluctuations in the amount of chemical components (such as bromide and dissolved oxygen) in the feed, and so on. Any experimental data, no matter how well a system is... 

A typical case arrives with the reaction wheel,whose perturbations frequency is dependent on the rotation speed (Fig. 6.27) it is therefore necessary to have a broadband active control of vibrations. 

Reaction Monitoring and Process Control by Vibrational Spectroscopy 283... 

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