title: Laser-enhanced ionization of mercury atoms in an inert atmosphere with avalanche amplification of the signal.
abstract: A new method for laser-enhanced ionization detection of mercury atoms in an inert gas atmosphere is described. The method, which is based on the avalanche amplification of the signal resulting from the ionization from a selected Rydberg level reached by a three-step laser excitation of mercury vapor in a simple quartz cell, can be applied to the determination of this element in various matrices by the use of conventional cold atomization techniques. The overall (collisional + photo) ionization efficiency is investigated at different temperatures, and the avalanche amplification effect is reported for Ar and P-10 gases at atmospheric pressure. It is shown that the amplified signal is related to the number of charges produced in the laser-irradiated volume. Under amplifier noise-limited conditions, a detection limit of ∼15 Hg atoms/laser pulse in the interaction region is estimated.
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200.
authors.forename: W L
authors.initials: WL
authors.lastname: Clevenger
authors.forename: O I
authors.initials: OI
authors.lastname: Matveev
authors.forename: S
authors.initials: S
authors.lastname: Cabredo
authors.forename: N
authors.initials: N
authors.lastname: Omenetto
authors.forename: B W
authors.initials: BW
authors.lastname: Smith
authors.forename: J D
authors.initials: JD
authors.lastname: Winefordner