In this paper we present the results of an experimental study of electronic energy transfer in xenon-argon and xenon-krypton gaseous mixtures excited by an a source. Spectroscopic evidence is presented for molecule-atom energy transfer from Ar*2(1,3Σu) to Xe( 1P1) and from Kr*2( 1,3Σu) to Xe(3P1). These two electronic energy transfer processes are characterized by large ∼ 10 -14 -10-13 cm2 cross sections. Information has been obtained for collision-induced energy conversion processes of the Xe energy acceptor involving 1P1→3P1 conversion and the formation of Xe*2(1'3Σ u) at moderately low (≤ 200 ppm) Xe concentrations. A new emission band, observed in the xenon-krypton system, peaking at 1530Å, is tentatively assigned to a heteronuclear (KrXe)* diatomic molecule.