Eric J. Zuckerman

Double-resonance spectroscopy of the high Rydberg states of HCO. V. Rovibronic interactions and l-uncoupling in the (010) manifold

We report the ionization-detected absorption spectra of autoionizing Rydberg states converging to the (010) vibrational level of HCO+. Sharp second-photon resonances appear in transitions from first-photon-prepared originating states that have total angular momentum (less-spin) from N′=0 to 5, selected from the Σ+ and Σ− components of the (010) band of the 3pπ2Π Rydberg state. We systematically compare spectra in order to characterize observed resonances in terms of the good total angular momentum quantum number, N. Rydberg analysis establishes the convergence of series to detailed cation-core rotational quantum numbers, N+. Observed series are found to fit well with simulations employing a limited set of constant quantum defects (δ=1.062, 0.794, 0.606, 0.253, 0.015, 0.002, −0.027 and −0.076). The strengths of observed transitions as a function of initial and final total angular momentum provide a purely experimental indication of the appropriate assignment of the approximately good orbital angular moment...

State–to–state dynamics in the high Rydberg states of polyatomic molecules

Rydberg states in polyatomic molecules exhibit dynamics that bear on issues of longstanding importance for theory. Coupling is made complicated, however, by the presence of many rovibrational degrees of freedom and the existence of multiple pathways for intramolecular relaxation. In work on vibrationally autoionizing states of HCO and NO2, we have applied multiple resonance excitation strategies to isolate single rovibrational Rydberg–Rydberg transitions, the positions, lineshapes and intensities of which reflect coupling strengths for state–detailed relaxation processes.