Excitation and decay of H−**(n = 3) Feshbach resonances in H− /raregas collisions

Abstract

Excitation of H−** resonances in H− /raregas collisions for energies from 2 to 7 keV has been studied. The resonances are observed usingtranslational electron spectroscopy. In addition to well known Feshbach resonances lying belowH (n = 2) and decaying to H(1s), we have identified Feshbach resonances lying belowH (n = 3) decayingto H (n = 2) andH(1s). The resonance profiles exhibit strong interference patterns, depending on the target gas. Resonancesbelow H (n = 4) have also been observed. Excitation of shape resonances lying above theH (n = 3) threshold is also suspected.