Electron drift velocity in argon, nitrogen, hydrogen, oxygen and ammonia in strong electric fields determined from rf breakdown curves

We report measurements of the breakdown curves for low-pressure rf capacitive discharges in nitrogen, hydrogen, argon, oxygen and ammonia. The electron drift velocity in these gases was deduced, as a function of reduced electric field, from the low-pressure turning points of the breakdown curves. The equation for rf breakdown proposed by Kihara (1952 Rev. Mod. Phys. 24 52) allows the position of both the turning point and the breakdown curve minimum to be calculated from the transport properties of each gas. Therefore we propose a new technique to determine the electron drift velocity from the position of the rf breakdown curve minima. We have determined the drift velocity in the range E/p ≤ 52-1324 V cm^-1 Torr^-1 for nitrogen, E/p ≤ 33-720 V cm^-1 Torr^-1 for argon, E/p ≤ 32-713 V cm^-1 Torr^-1 for ammonia, E/p ≤ 32-550 V cm^-1 Torr^-1 for hydrogen and E/p ≤ 69-1673 V cm ^-1 Torr^-1 for oxygen.