Repulsive van der Waals and Dipole-Quadrupole Interaction in the Excited LiCs Molecule

Abstract

The authors report strong repulsive van der Waals and dipole-quadrupole interactions in the $\ensuremath{\Sigma}$ and $\ensuremath{\Pi}$ potentials of the LiCs molecule dissociating into Li $2P$ and Cs $6S$ atoms. Theoretical results derived from second-order perturbation theory are verified by investigating experimentally the wavelength dependence of the quasistatic wings of the Li resonance lines broadened by Cs ground-state atoms.