Resonant branching ratios

Note that, if Sb depends on the energy E, the eigenvector corresponding to the largest Q-matrix eigenvalue qmax depends on E and does not directly give the resonance branching ratios IV T however, see Ref. [50]. 

Eibium thin films 5.4. Resonant branching ratios... 

The kinetics study [38] utilized a Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer to measure the pathway branching ratios. The ability to eject selected masses and the extremely high mass resolution of this technique ensured that the observed CD3CH2 was in fact a primary product of the reaction. Temporal profiles from this reaction are shown in Fig. 1. Noticeably absent from the mass spectrum are the cations C2D2H3 and... 

There are several considerations to bear in mind when using fluorescence detection. First, the approach is most useful when the photons to be detected have a vastly different wavelength than the exciting light and the most probable decay of the optically excited state, which need not be the same. Second, the branching ratio for the detected transition should be favorable. Third, the lifetimes of the initial and final state of the microwave transitions must be taken into account. If the microwaves are always on, at resonance, radiative decay occurs from the coupled pair of states. If the initial state of the microwave transition has a much... 

The dynamics of a reaction that proceeds directly over the transition state is expected to be qualitatively different from that of a resonance-mediated reaction. In particular, one expects that the branching ratios into the product rovibrational states will be very different between the direct and the resonant mechanisms. For example, if a given Feshbach resonance corresponds to trapping on the v = 1 vibrationally adiabatic curve, then one might expect that the population of the v = l vibrational state of the product molecule may be greatly enhanced by the resonant mechanism. Similarly, the rotational product distribution resulting from the fragmentation of a resonance molecule may show a quite distinct pattern from that of a direct reaction. Indeed, Liu and coworkers [94], and Nesbitt and coworkers [95] have noted distinct rotational patterns in the F+HD resonant reaction. 

B.C. Garrett, D.W. Schwenke, R.T. Skodje, D. Thirumalai, T.C. Thompson, D.G. Truhlar, Adiabatic and Nonadiabatic Methods for Energies, Lifetimes, and Branching Ratios of Reactive Resonances in Bimolecular Collisions, ACS Symposium Series 263, American Chemical Society, Washington DC, 1984,375. 

L. Argenti, E. Lindroth, Ionization branching ratio control with a resonance attosecond clock, Phys. Rev. Lett. 105 (2010) 053002. 

This type of two-photon vs. two-photon phase control has been implemented experimentally in molecules by Pratt [208], who studied the photoionization of the ri2E+. ij — 1 state of NO, and in atoms by Elliott s group [209], who demonstrated control over the branching ratio for photoionization of Ba into the 6s1/2, 5d3/2 and 5d5/2 states of Ba+. Quite unexpectedly, the interference between the two-photon routes turned out to be destructive when both lasers were resonant with their respective transitions. A theoretical treatment of effect was provided by Luc-Koenig et al. [210],... 

We see that / (i, t) displays damped Rabi-type oscillations between the initial state and the final continuum states, where the damping is given by resonance decay rate TJ2h. Although the frequency of the Rabi oscillations is a function of the fieldib strength 0, the branching ratio between channels is independent of the laser para- 4... 

Many semi-classical and quantum mechanical calculations have been performed on the F + H2 reaction, mainly being restricted to one dimension [520, 521, 602]. The prediction of features due to quantum-mechanical interferences (resonances) dominates many of the calculations. In one semi-classical study [522], it was predicted that the rate coefficient for the reaction F (2P1/2) + H2 is about an order of magnitude smaller than that for F(2P3/2) 4- H2, which lends support to the conclusion [508] that the experimental studies relate solely to the reaction of ground state fluorine atoms. Information theory has been applied to many aspects of the reaction including the rotational energy disposal and branching ratios for F + HD [523, 524] and has been used for transformation of one-dimensional quantum results to three dimensions [150]. Linear surprisal plots occur for F 4- H2(i> = 0), as noted before, but non-linear surprisal plots are noted in calculations for F + H2 (v < 2) [524],... 

The ability of CPT to separate two enantiomers also depends on the individual detuning parameters Ay and on the related dynamical phase 2 2 r. At resonance Ay = 0 and

population transfer from state 1) to a combination of states 2) and 3). In that case, the p2/p3 branching ratio of the final populations is given, as in the double STIRAP case [98,99], by the IfWfinl2 ratio, and no enantiomeric selectivity is then possible. 

The large branching ratios predicted by the multiple scattering model is certainly an Indication of the poor representation of the R dependence of the molecular ion potential in this model. It is important to note that substantial non-Franck-Condon behavior of this branching ratio occurs at photon energies well above the peak position of the resonance (27). 

The theoretical predictions discussed above were soon tested In two separate experiments. In Figure 8 the branching fxtlg or production of the v 0 and 1 vibrational levels of nT X Is shown. The dash-dot line is the original prediction C40). "The solid dots are the recent measurements (46) in the vicinity of the shape resonance at hv 30 eV. The conclusion drawn from this comparison Is that the observed variation of the vibrational branching ratio relative to the FC factor over a broad spectral range qualitatively confirms the prediction however, subsequent calculations (7,48) with fewer approximations have achieved better agreement based on the same mechanism for breakdown of the FC separation. The dashed and solid curves are results based on a... 

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