Photodissociation spectroscopy of the dysprosium monochloride molecular ion

Abstract

We have performed a combined experimental and theoretical study of the photodissociation cross section of the molecular ion DyCl$^+$. The photodissociation cross section for the photon energy range 35,500 cm$^{-1}$ to 47,500 cm$^{-1}$ is measured using an integrated ion trap and time-of-flight mass spectrometer; we observe a broad, asymmetric profile that is peaked near 43,000 cm$^{-1}$. The theoretical cross section is determined from electronic potentials and transition dipole moments calculated using the relativistic configuration-interaction valence-bond and coupled-cluster methods. The electronic structure of DyCl$^+$ is extremely complex due to the presence of multiple open electronic shells, including the 4f$^{10}$ configuration. The molecule has nine attractive potentials with ionically-bonded electrons and 99 repulsive potentials dissociating to a ground state Dy$^+$ ion and Cl atom. We explain the lack of symmetry in the cross section as due to multiple contributions from one-electron-dominated transitions between the vibrational ground state and several resolved repulsive excited states.