Constriction in lithium glow discharges in a heat-pipe oven

The electric discharge was established in a modified crossed heat-pipe oven filled with lithium. The discharge was spectroscopically studied for diffe rent lithium vapor pressures. Constriction of the positive column in the li thium vapor discharge was observed and the discharge diameter was measured as a function of lithium vapor pressure. The rich bound-bound emission mole cular spectra of A(1)Sigma(u)(+) --> X(1)Sigma(g)(+) and B(1)Pi(u) --> X(1) Sigma(g)(+) systems of the lithium dimer were observed in lithium-rare gas discharges and correlated with the onset of the discharge constriction. (C) 1999 Elsevier Science B.V. All rights reserved.