Photoexcitation and predissociation of singlet ungerade rydberg states of molecular hydrogen
Yoon, Sang Il
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Decay rate and excitation cross section are important photophysical parameters which are difficult to be measured. However, experimentally measured values can be compared to theory as a check. In this study, a new technique has been employed to deduce excitation cross sections and decay rates of singlet, ungerade np excited states of molecular hydrogen. Theses photophysical properties of the Rydberg states with principal quantum number n=4 to 7 will be investigated by analyzing the observed spectra of a Resonantly Enhanced Multiphoton ionization/excitation(REMPI) experiment in comparison to the results of model calculation. Experimentally, two separate ionization yields, H2(from photoionization) and H'^(from predissociation), have been observed, and consequently predissociation line widths and ionization dip depths or peak heights have been obtained. Then, using these values, excitation cross section of the transition and predissociation rate will be obtained by solving a system of detailed rate equations when a dip appears in the Hj ionization yield. In the case of peak in the Hj ionization yield, predissociation and photoionization yields will be directly compared to gain qualitative information on decay dynamics.