Vibrational energy distributions of the

Figure 2. Vibrational energy distribution of the CO product formed via the 351 nm photolysis of W(CO)s. Experimental data are indicated asfl. The lines correspond to results obtained by phase space calculations with an available energy of 40 and 35 Kcal/mole.

Shapiro, M. and Bersohn, R. (1980). Vibrational energy distribution of the CH3 radical photo dissociated from CH3I, J. Chem. Phys. 73, 3810-3817. 

Figure 2. Vibrational energy distributions of the CO formed in 0(3P) + CtHt (O) and Of3P) + CtH,CsH reactions (-----------), are statistically prodicted distribu-...

Pig. 1. Vibrational energy distribution of the products of the reaction Cl+HI -> I+HCl (from Gallis and Harvey ). 

Fig. 13. Vibrational energy distribution of the CO formed in the methylketene photodissociation in Vycor triangles, 2% CH2CHCO in SF open circles, 5% CH3CHCO in SF solid circles, 0-1-CH3C2H reaction. Reprinted with premission from J. Phys. Chem., 82, 1458 (1978). Copyright by the American Chemical Society.

In the experiment by Jean et al. [12], they used trans-stilben as a solute and hexane as a solvent. The temperature of the solution is kept at 295 2 K. After trans-stilben is electronically excited by a laser pulse, the intensities of the anti-Stokes Raman shifts are measured by changing the time interval after the pulse. Thus, they observed the time dependence of the vibrational energy distribution of the solute molecule. Figures 3.8 and 3.9 display their results. 

This woik on Xe-X2 is still not fully completed, and will need some two independent colour experiments for example. Nevertheless it shows that the van der Waals technique brings some new information on the reactive surface, and that the selectivity upon the entrance channel geometry leads to a very drastic effect upon the vibrational energy distribution of the products. 

In order to understand the dynamics of the 0 + CF reaction occurring in the SO2 - CFBr3 chemical CO laser system, we carried out CO laser resonance absorption experiments to measure the vibrational energy distribution of the CO formed in the reaction. A detailed description of the flash-photolytic CO laser-probing system can be found in reference (19). Experiments were carried out using both Suprasil ( S 165 nm) and quartz ( - 200 nm) flash tubes for mixtures of CFBr3 SOj with He as a diluent. With the Suprasil tube, 10-torr samples of a 1 1 98/CFBr3 SO2 He mixture were used, whereas with the quartz tube 5-torr samples of both the 1 1 98 and 1 1 48 mixtures... 

If T2>T, then AS>0 since Cp and T are >0. From a molecular point of view, heating a solid increases the amplitudes and energy distributions of the vibrations of the molecules in the solid, resulting in increased disorder. 

It should also be mentioned that a theoretical model using an empirical LEPS potential energy surface has successfully been used to reproduce the vibrational population distribution of the products of this surface reaction.40 This approach confines itself to the assumptions of the Born-Oppenheimer approximation and underscores one of the major questions remaining in this field do we just need better Born Oppenheimer potential surfaces or do we need a different theoretical approach ... 

Nonequilibrium effects. In applying the various formalisms, a Boltzmann distribution over the vibrational energy levels of the initial state is assumed. The rate constant calculated on the basis of the equilibrium distribution, keq, is the maximum possible value of k. If the electron transfer is very rapid then the assumption of an equilibrium distribution over the energy levels is not valid, and it is more appropriate to treat the nuclear fluctuations in terms of a steady-state rather than an equilibrium formalism. Although a rigorous treatment of this problem has not yet appeared, intuitively it seems that since the slowest nuclear fluctuation will generally be a solvent orientational motion, ke will equal keq when vout keq and k will tend to vout when vout keq (a simple treatment gives l/kg - 1/ vout + 1/keq). These considerations are... 

Fig. 5.5. Comparison of quantum mechanical and classical vibrational state distributions of the OD and OH products following the dissociation of HOD in the first continuum. The energies are E = -2.5 eV (top), -2.2 eV (middle), and —1.9 eV (bottom), respectively. Energy normalization is such that E = 0 corresponds to H + O + D. Reproduced from Engel and Schinke (1988).

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