Pink Light (Lithium)?

[YT2095]

I wasn`t sure where to put this, either here or Physics? but here goes...

 

I`ve basicly built a a Vacuum tube with a conductor at each end that I may pass electricity into, + one end and -the other.

to increase the vacuum potential, other than removing as much air as possible whilst very hot and sealing the glass evacuation tube, I also added half a gram of Lithium metal into the chamber prior to this.

in hopes of removing any residual gasses incl Nitrogen.

 

I`ve just applied roughly 25kv across these 2 electrodes and have the most beautifull Pink Arc going between them.

 

How is this possible? lithium cannot be a gas at room temp, and the vacuum isn`t THAT GOOD to vaporise it surely? most of the Lithium is now White/Grey (I made this thing nearly 2 years ago), and there is some powder loose also, BUT...

 

how can I be getting Lithium Pink from this?

[jdurg]

Hydrogen gas and oxygen gas also give off a pink color in a vacuum tube. Unless your tube is 100% evacuated (which I can gaurantee you it is not), there will always be some type of residual gas in there. If you have lithium metal and there was some water vapor inside the tube, there's a high possibility that hydrogen gas has been produced. That would easily describe the pink color. You may want to go and pick up a cheap spectrometer device so that you can see the exact spectrum being generated by the tube.

[YT2095]

well I`m looking at the spectra for h2 in my book at this moment and see markers for 656 486 434 410 397 384 and 380 nm.

there are other trace identifiers of a lower level, but I`m thinking that the 397 marker maybe the candidate here if it is hydrogen?

and there`s no need to tell me it isn`t 100% evacuated, I KNOW it aint,

it would Glow and not arc at these voltages

[swansont]

You're always going to have some of the Lithium around as a gas, because it has a nonzero vapor pressure.

[YT2095]

well I must admit, the color I see is remarkably Lithium(ish) if that makes sense at all.

also ignore what I said about the vacuum, it`s actualy Great! I forgot to factor in that just because is doesn`t Glow visibly doesn`t mean that current isn`t passing and that no "Light" isn`t given off, it only arcs when it spikes, IE/ I allow the voltage to Arc to the external electrode, but on a dead contact, it SEEMS to do nothing beyond a slight corrona discharge on the needle tip and the target plate (I originaly intended it as an X-Ray tube), but haven`t tested that side of things yet, as today was the 1`st time I`ve managed to build a PSU good enough to power it.

the Vacuum`s Fantastic!