Radiative lifetimes of even- and odd-parity levels in Sc i and Sc ii

Abstract

Time-resolved laser-induced fluorescence on atomic and ionic beams is used to measure radiative lifetimes for 77 odd- and even-parity levels of Sc i and Sc ii. Time-of-flight selection of slow scandium atoms is demonstrated to minimize a systematic error in long lifetimes, an error that arises because atoms escape from the observing region before radiating. High-lying even-parity levels in Sc i and Sc ii are excited by using two-step laser excitation.