FORMATION OF METASTABLE EXCITED TI AND NI ATOMS DURING ION SPUTTERING

Metastable excited neutral Ti and Ni atoms in electronic states with energies up to approximately 0.2-eV excitation energy, ion sputtered from polycrystalline samples, have been analyzed with respect to their relative population and their velocity distribution. The influence of the electronic configuration (a3F for Ti and a3F and a3D for Ni) on the population and energy distribution has been investigated. The targets have been bombarded with 8.0 keV Ar+ ions under a 45° angle of incidence. The sputtered secondary neutrals were ionized by resonant one-color two-photon laser radiation and mass analyzed in a time-of-flight mass spectrometer. The population of all excited metastable states in the energy regime up to 0.1 eV have been found comparable to the ground-state population. The velocity distribution of the ground and excited states, regardless of their excitation energy and electronic configuration, have been found identical and governed by the collision cascade following the ion impact. © 1995 The American Physical Society.