XeCl excimer

The chlorine cousin of XeF: xenon plus a chlorine carrier, assembling XeCl in the discharge. The molecule radiates in the near ultraviolet at 308 nm, which is laser territory; the eye gets the violet spill-over and whatever the buffer adds. In some frames the vessel runs as a plasma jet, a needle of light standing off the glass, while the fill swirls teal and lilac like weather.

Periodic Table of Plasma