Adsorption interaction of carrier-free thallium species with gold and quartz surfaces

The adsorption interactions of thallium and its compounds with gold and quartz surfaces were investigated. Carrier-free amounts of thallium were produced in nuclear fusion reactions of alpha particles with thick gold targets. The method chosen for the studies was gas thermochromatography and varying the redox potential of the carrier gases. It was observed that thallium is extremely sensitive to trace amounts of oxygen and water, and can even be oxidized by the hydroxyl groups located on the quartz surface. The experiments on a quartz surface with O₂, He, H₂ gas in addition with water revealed the formation and deposition of only one thallium species - TlOH. The adsorption enthalpy was determined to be ΔHSiO_{2 ads} (TlOH)=-134±5 kJmol^-1. A series of experiments using gold as stationary surface and different carrier gases resulted in the detection of two thallium species - metallic Tl (H₂ as carrier gas) and TlOH (O ₂, O₂ +H₂O and H₂ +H₂O as pure carrier gas or carrier gas mixture) with ΔH^Au _ads(Tl)=-270±10 kJ mol^-1 and ΔH^Au _ads(TlOH)=-146±3 kJmol^-1. These data demonstrate a weak interaction of TlOH with both quartz and gold surfaces. The data represent important information for the design of future experiments with the heavier homologue of Tl in group 13 of the periodic table - element 113 (E113).