Rare Earth oxide equilibria in pulsed direct current glow discharge mass spectrometry

Glow discharge mass spectrometry is used to examine the equilibria existing between La(+) and LaO(+). A pulsed discharge permitted temporal comparison of spectra taken at varying intervals after discharge initiation. Postdischarge peaks are observed for both atom and oxide ions. By varying the pulse period while sustaining a fixed "on" time, the degree of deposition of gaseous constituents on the cathode surface can be controlled. Injection of normal water and isotopically labeled water for compacted and noncompacted samples allows insight into the source of water signals.