Novel molecular discharge light sources

Abstract

A systematic investigation into transition metal halides and oxides showed the high potential of transition metal oxides as visible radiators for highly efficient gas discharge light sources. Zirconium monoxide (ZrO) has been identified as the most promising candidate combining highly attractive green and red emission band systems with very high dissociation energy (8.2 eV) which ensures that the molecule is stable even at the hot plasma centre. Thus far, however, it has been impossible to keep ZrO in the gas phase of a closed discharge vessel, because at wall temperature usually compounds are formed which have negligible vapour pressures. We succeeded in establishing a regenerative chemical cycle by filling ZrX4 (X = Cl, Br, I) together with a stable, but volatile oxygen compound (like MoO2X2) and realized thus highly attractive, novel gas discharge light sources.