Differential cross-section state-resolved

Schnieder L, Seekamp-Rahn K, Wede E and Welge K H 1997 Experimental determination of quantum state resolved differential cross sections for the hydrogen exchange reaction H -r D2 -> HD -r D J. Chem. Phys. 107 6175-95... 

The generalized Prony analysis of END trajectories for this system yield total and state resolved differential cross-sections. In Figure 5, we show the results. The theoretical analysis, which has no problem distinguishing between the symmetric and asymmetric str etch, shows that the asymmetric mode is only excited to a minor extent. The corresponding state resolved cross-section is about two orders of magnitude less than that of the symmetric stretch. 

In the context of the present chapter, only the differential cross-section (DCS) results will be reviewed.27,31 The DCS obtained by experiment and theory27 are shown in Figs. 17-19. In Fig. 17 we show the experimental total angular distributions, da/dfl, around the 0.5 kcal/mol feature obtained by summing over all (vj ) states of the HF products. (The resolution was sufficiently high to resolve most of the product rovibrational states for j > 4... 

Figure 3. State resolved differential cross-section versus laboratory scattering angle for vibrational excitation of hydrogen molecules into state v = 4 in single collisions with 30-eV protons.

Figure 4. The experimental [50] total and three-state resolved differential cross-sections of vibrational excitations of the water molecule in collisions with 46-eV protons.

Syage, J. A., Photofragment Imaging by Sections for Measuring State-Resolved Angle-Velocity Differential Cross Sections, J. Chem. Phys., 105, 1007-1022 (1996b). 

It is clear that the unmistakable resonance fingerprint provided by a narrow Lorentzian peak in the integral cross section (ICS) will be rare for reactive resonances in a collision experiment. However, a fully resolved scattering experiment provides a wealth of data concerning the reaction dynamics. We expect that the state-to-state differential cross sections (DCS) as functions of energy can be analyzed, using various methods, to reveal the presence of reactive resonances. In the following subsections, we discuss how various collision observables are influenced by existence of a complex intermediate. Many of the resonance detection schemes that have been proposed, such as the use of collision time delay, are purely theoretical in that the observations required are not currently feasible in the laboratory. Nevertheless, these ideas are also discussed since it is useful to have method available... 

Bergmann, K., Engelhardt, R., Hefter, U. and Witt, J. (1978). State-resolved differential cross sections for rotational transitions in Na2 + Ne(He) collisions, Phys. Rev. Lett., 40, 1446-1450. 

The main difference between the new potential and that of Buck et al., i.e. the depth of potential wells, cannot be verified by this high energy scattering calculation in order to provide major insights, work is in progress to compute the MO-VB PES at a higher level of theory and to calculate differential cross-sections at the lower collision energy of 275 cm 1 [69], where total inelastic and some state resolved differential cross sections are available [65]. 

The differential cross section is defined for experiments that do not resolve angular-momentum projections or observe polarisations. States with different values of these observables are degenerate. We average over initial-state degeneracies and sum over final-state degeneracies. In the absence of details of the states this is denoted by Lav- The final form of the differential cross section is... 

Differential and Integral Cross Sections. In Figure 7 are shown the state-to-state 1-average reactive differential cross sections for F-fH2 (degeneracy-averaged over m., summed over m and but resolved with respect to the final vibrational state v ). In each figure. 

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