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.