Large amplitude motion of the acetylene molecule within acetylene–neon complexes hosted in helium droplets

Abstract

Superfluid helium droplets provide an ideal environment for spectroscopic studies with rotational resolution. Nevertheless, the molecular rotation is hindered because the embedded molecules are surrounded by a non-superfluid component. The present work explores the dynamical role of this component in the hindered rotation of C₂H₂ within the C₂H₂–Ne complex. A HENDI experiment was built and near-infrared spectroscopy of C₂H₂–Ne and C₂H₂ was performed in the spectral region overlapping the ν₃/ν₂ + ν₄ + ν₅ Fermi-type resonance of C₂H₂. The comparison between measured and simulated spectra helped to address the above issue.