Reaction product energy distributions

LASER DIAGNOSTICS OF REACTION PRODUCT ENERGY DISTRIBUTIONS... 

Laser Diagnostics of Reaction Product Energy Distributions... 

Master equations CH2O, reaction, populations CF2Br2, C2F5I, reaction, product energy distributions from adiabatic channel model 75... 

Table B2.5.3. Product energy distribution for some IR laser chemical reactions. (E ) is the average relative translational energy of fragments, is the average vibrational and rotational energy of polyatomic fragments, and/ is the fraction of the total product energy appearing as translational energy [109],...

Figure 3. Product energy distributions for the Cl" CHaBr - CICH3 + Br reaction histogram, trajectory result 6 dashed line, experiment 29 and solid line, prediction of OTS/PST. The trajectory results are scaled to match the experimental exothermicity.

Reaction dynamics as opposed to reaction kinetics strives to unravel the fundamentals of reactions—just how they transpire, how intramolecular vibrational energy redistributions provide energy to the modes most involved along the reaction coordinate, how specihc reaction states progress to specihc product states, why product energy distributions and ratios of alternative products are as they are, and, of course, how fast the basic processes on an atomic scale and relevant timeframe occur. 

The approach described for polyatomic photodissociation as a quantum transition can be generalized to describe the dynamics of chemical reactions. Polyatomic photodissociation is a transition from a quasi-bound or bound state to a bound-continuous dissociative state. By extension then, a chemical reaction is a transition from one bound-continuous state (reactants) to another (products). The state of reactants (products) is analogous to the dissociative state and, hence, the results described in Section III can be used to define the nuclear wavefunctions of reactants and of products. Following this analogy, a chemical reaction can be treated as a quantum transition reactants - products, enabling the evaluation of product energy distributions (63,33). 

Trajectory calculations for proton transfer and ionization in water cluster,112 116 isomerization,117 and various types of unimolecular reactions6,118 128 have been carried out, and the analyses on time course of the reaction, product ratio, and product energy distribution were reported. 

However, with the exception of a few coplanar studies, all other quantum calculations have been for ID systems. The extent to which ID calculations form a satisfactory basis to explain the energy disposal in chemical reactions varies from reaction to reaction and, in the absence of experimental information or more approximate calculations, is impossible to assess. Collinear calculations need to be transformed to three dimensions in an attempt to incorporate the effects of orbital and rotational angular momentum which are absent in the ID calculations and produce more realistic product energy distributions [149,150]. Such methods appear to work most effectively for reactions whose dynamics are predominantly collinear. 

Information theory was first applied [177] to chemical reactions in an attempt to compact and classify the energy distributions of reaction products. This is achieved by surprisal analysis, where the observed product energy distribution, say for vibration, P(v ), is compared with a non-specific prior distribution P°(v ). Then, the surprisal, I(v ), is given by... 

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