Abstract

Although the group IIB metal dimers (Zn₂, Cd₂, Hg₂) have received considerable attention as potential bound → free (excimer) lasers, little is known of the electron ic excited states above the lowest-lying level (³Π_g). This paper describes experiments in which the absorption spectrum of Zn₂(4p³Π_g) in the visible and ultraviolet has been observed. A quartz cell containing several milligrams of zinc was evacuated to < 10^-7 Torr, sealed and heated to ~800°C. Excited Zn atoms were produced by pumping the atomic 4p³P₁ ← 4s²¹S₀ transition at 307.6 nm with an untuned XeCI laser. Diatomic molecules are subsequently formed in three-body collisions of a 4p³P₁ atom with two background ¹S₀ species. A pulsed Xe lamp (~300-nm FWHM) provided the probe continuum. Collimated and spatially filtered, the beam from the lamp propagated through the XeCI laser-produced excited region and was detected by a 0.25-m spectrograph/diode array combination. The UV and visible are dominated by absorption bands centered at 290,390, and 420 nm. Weaker but significant bands in the 450-460-nm region are also observed. Spectroscopic identification of these bands is discussed.

© 1986 Optical Society of America