Degenerate and two‐color resonant four‐wave mixing of C2− in a molecular beam environment

Abstract

AbstractIn this paper, we demonstrate that degenerate and two‐color resonant four‐wave mixing spectroscopy is applicable for the sensitive and selective characterization of negative ions in a molecular beam environment. Results are shown for C$_{2}^{-}$, which is produced by discharging a mixture of acetylene and argon prior to supersonic expansion. Substantial signal‐to‐noise ratios of ≈ 150 show that the method is generally applicable for high‐resolution optical double‐resonance spectroscopy of negative ions. A detection sensitivity for C$_{2}^{-}$ of ≈ 107 ions/cm3 is estimated. Copyright © 2010 John Wiley & Sons, Ltd.