Bright hydrogen-light source due to a resonant energy transfer with strontium and argon ions

A plasma called a resonant transfer (rt) plasma formed with a low field (1 V cm^-1), at low temperatures (e.g. ≈10³ K), from atomic hydrogen generated at a tungsten filament and strontium which was vapourized by heating the metal. Strong vacuum ultraviolet emission was observed that increased with the addition of argon, but not when sodium, magnesium or barium replaced strontium or with hydrogen, argon or strontium alone. Characteristic strontium and argon emission was observed which supported a resonant-energy-transfer mechanism. Significant Balmer α line broadening corresponding to an average hydrogen atom temperature of 14, 24, and 23-45 eV was observed for strontium and argon-strontium rt plasmas and discharges of strontium-hydrogen, helium-hydrogen, argon-hydrogen, strontium-helium-hydrogen and strontium-argon-hydrogen, respectively, compared to ≈3 eV for pure hydrogen, krypton-hydrogen, xenon-hydrogen and magnesium-hydrogen. To achieve that same optically measured light output power, hydrogen-sodium, hydrogen-magnesium and hydrogen-barium mixtures required 4000, 7000 and 6500 times the power of the hydrogen-strontium mixture, respectively, and the addition of argon increased these ratios by a factor of about two. A glow discharge plasma formed for hydrogen-strontium mixtures at an extremely low voltage of about 2 V compared to 250 V for hydrogen alone and sodium-hydrogen mixtures, and 140-150 V for hydrogen-magnesium and hydrogen-barium mixtures.