Rydberg tagging schemes

Finally, it is only right that we conclude this chapter with a further mention of the group that first demonstrated the virtues of the H-atom photofragment translational spectroscopy technique. Over the past few years, Welge, Schnieder, and co-workers [391,392] have concentrated much of their efforts on applying the same Rydberg tagging schemes to the... 

Compared to the H-atom Rydberg tagging technique,65 the resolution of the present method is somewhat worse, by about a factor of two. This loss in resolution, however, is realized in general only for photodissociation studies. In a typical crossed beam experiment, the product translational energy resolution is usually limited by the energy spread of the initial collision energy rather than the detection scheme. On the other hand, the present... 

Fig. 1. Detection schemes for H-atoms. Rydberg tagging technique is slightly different from the (1 + l )-REMPI detection scheme in which the H atom is directly ionized Rydberg tagging only pumps the H atom to a high Rydberg state.

H2 molecular beam. The H-atom products were detected by the Rydberg tagging TOF technique using the same scheme described in the last paragraph with a rotatable MCP detector. Figure 4 shows the experimental scheme of the crossed beam setup for the 0(1D) + H2 reactive scattering studies. The scheme used for the H + D2(HD) studies is very similar to that used in the 0(1D) + H2 except that the H-atom beam source is generated from HI photodissociation rather than the 0(1D)-atom beam source from 02 photodissociation. 

Figure 3. Two variants of the two-color two-photon tagging scheme used in the H(D) atom photofragment translational spectroscopy technique. Early implementations used the two-color two-photon threshold ionization scheme shown on the left, but in all recent high-resolution work the second photon has been chosen so as to excite a high n Rydberg state lying at an energy just below the ionization limit.

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