Angle-resolved velocity distributions of excited Rh atoms ejected from ion-bombarded Rh{100}

The distributions of metastable excited state (⁴F_7/2) and ground state (⁴F_9/2) Rh atoms ejected from Ar ⁺-bombarded Rh{100} are experimentally determined as a function of ejection velocity and angle. Corresponding theoretical predictions are made by incorporating a nonradiative deexcitation model into molecular dynamics simulations of the bombardment process. There is good agreement between the experimental and theoretical distributions. The simulations show that a fraction of the ejected atoms are excited via collisions 1-20 Å above the surface, and that these atoms make a significant contribution to the excited atom yield at low ejection velocities.