Probing potential energy curves of C₂^- by translational energy spectrometry distribution

Abstract

We present studies on collision induced dissociation of C₂ ^- with Ar at an impact energy of 15 keV. The C^- fragment ion Kinetic-Energy Release (KER) distribution is measured and is used to compute the KER in the center of mass (c.m.) frame (KER_c.m.). We employ the reflection method to deduce an effective repulsive potential-energy curve for the molecular anion that is otherwise difficult to evaluate from quantum computational methods. The nuclear wave packet of the molecular ion in the initial ground state is computed by the semiclassical WKB method using the potential-energy curve of the ² Σ_g⁺ ground electronic state calculated by an ab initio quantum computation method. The ground-state nuclear wave packet is reflected on a parametrized repulsive potential-energy curve where the parameters are determined by fitting the measured KER_c.m. with the calculated KER distribution.