Knowledge Bank

We have obtained $(1+1\prime )$ double resonance spectra autoionizing high Rydberg states of HCO. Scans originate from $3p\pi \mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi N=0-5$ intermediate states. These spectra cover Rydberg states of binding energies ranging from 650 to $400cm-1$, converging to the (010) fundamental of $HCO+$. Using our highly accurate ionization thresholds and by applying the Rydberg model, simulations which neglect coupling are found to reasonably represent the experimental spectra within a minimal quantum defect basis. Analysis based on Multichannel Quantum Defect Theory, which includes coupling, is underway.