Excitation functions resonances

Indeed, several identifiable resonance fingerprints in experimental observables were found.26-31 Concurrent theoretical simulations and analyses not only confirmed the experimental conjectures, but also provided deeper insights into the nature of this resonance state. For the integral cross-sections, a distinct step for Ec < 1 kcal/mol was observed in the reactive excitation function (i.e. the translation energy dependence of the reactive cross-section) for the HF+D product channel, whereas it is totally absent for the other DF+H product channel.26 Anomalous collision energy dependence of the HF vibration branching was also observed.28 For Ec < 1 kcal/mol more than 90% of the HF products are populated in the v = 2 state. However, as the energetic threshold for the formation of HF( / = 3) from... 

Fig. 3. The normalized excitation functions in A2 versus collision energy for the two isotopic channels for the F+HD reaction. The solid line is the result of quantum scattering theory using the SW-PES. The QCT simulations from Ref. 71 are plotted for comparison. The experiment, shown with points, is normalized to theory by a single scaling factor for both channels. Also shown in (a) is the theoretical decomposition of the excitation function into direct and resonant contributions using the J-shifting procedure.

Excitation Eunctions of O2 and 02-Doped Ar Eilms. Resonances can be best identified by the structures they produce in excitation functions of a particular energy-loss process (i.e., the incident-electron energy dependence of the loss). Fig. 7 is reproduced from a recent study [118] of the electron-induced vibrational and electronic excitation of multilayer films of O2 condensed on the Pt(lll) surface and shows the incident electron energy dependence of major losses at the indicated film thickness and scattering angles. Also shown in this figure is the scattered electron intensity of the inelastic background... 

Figure 5.14 The helium ionization yield for the ion being left in the He+(2s) and He+(2p) excited states as a function of the time delay between the initial XUV pump pulse and the IR probe pulse. The oscillations are due to breathing between different doubly excited states (resonances).

Figure 26 Quadrupole moment Aq2) for the desorption of CO (v = 0) from 0 203(0 001) as a function of J. Filled circles show experimental data, solid lines show calculated Aq2) averaged with respect to the desorption velocity and other marks connected by line are calculated by various imaginary flat PESs. The excited state resonance lifetime tr = 10 fs [79].

Peticolas was the first to measure the UV resonance Raman spectrum and excitation profile (resonance Raman intensity as a function of excitation wavelength) of adenine monophosphate (AMP) [147, 148], The goal of this work, besides demonstrating the utility of UV resonance Raman spectroscopy, was to elucidate the excited electronic states responsible for enhancement of the various Raman vibrations. In this way, a preliminary determination of the excited-state structures and nature of each excited electronic state can be obtained. Although the excited-state structural dynamics could have been determined from this data, that analysis was not performed directly. 

The broad peaks at 6 and 10 eV, which are present in the yield functions for various types of DNA damage, are likely to be due to the formation of core-excited or core-excited shape resonances, since the lifetime of such resonances is usually sufficiently long to promote dissociation of the anion. A priori, scission of the C-O bond leading to SB can occur by direct electron capture on the phosphate group... 

In the resonance region, where the excitation functions exhibit sharp resonances, the cross sections of the individual reactions can be calculated from the line widths of the resonance lines by application of the Breit-Wigner formulas derived in 1936. Emission of neutrons from compound nuclei is preferred over emission of protons and relatively high cross sections are expected for (p, n) and (a, n) reactions if the energy of the incident particles is > 1 MeV. 

In Figure 4 we show the transmission spectrum of benzene at higher energies. The lowest feature Is the second "shape" resonance ( B2g). Above this lie several smaller features which must correspond primarily to core-excited states. Detailed studies of the decay channels of these resonances have not yet been carried out, although some Information is available. The vertical arrows in Figure 4 indicate the energies at which maxima occur in the excitation functions for Vi of the ground electronic state of ben-... 

With decay channel in the three excitation functions of Fig, 1(b) can be explained by finite llfetltne oscillator models (30-33) such as the "boomerang model (30-31)). Such an energy dependence on decay channel indicates that the lifetime of the resonance is comparable to the vibrational period. These findings suggest that the short-range part of the e -N2 potential well is not significantly modified in the solid and consequently, that the anion retains essentially the symmetry. 

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