title: Laser-enhanced electron-impact ionization spectroscopy.
abstract: Sequential photon-excitation, electron-impact ionization with subsequent mass analysis has been applied to a barium atomic beam. High-resolution, Doppler-free laser excitation produces the 6s6p(1)P(1) excited state, which is then ionized by electron bombardment. The excited state is selectively ionized when bombardment energies are between the excited- and ground-state ionization thresholds. Mass discrimination has permitted the recording of individual optical spectra for all the stable isotopes, including the 0.1% abundant (130)Ba and (132)Ba, in a sample with natural isotopic abundances.
authors.forename: B A
authors.initials: BA
authors.lastname: Bushaw
authors.forename: B D
authors.initials: BD
authors.lastname: Cannon
authors.forename: G K
authors.initials: GK
authors.lastname: Gerke
authors.forename: T J
authors.initials: TJ
authors.lastname: Whitaker