FWHM of the Lorentzian needed to reproduce the broadening is around 0.27 Angstrom (preliminary). To what pressure does that correspond....Uf, Uf... Working on it...

Using the values for the ``broadening constant'' from paper ``Pressure broadening and oscillator strengths in Argon'' (attached), measured broadening, and using insights from https://www.semrock.com/measuring-light-with-wavelengths-wavenumbers.aspx to convert weird units I get that number density of Argon in our lamps is 2.5x10**22 atoms in L, i.e., around 0.04 mol in a liter. This is what one would expect if this Argon is under standard conditions (1/22.4 mol in a liter). I think our lamps are under-pressured, but perhaps on a bit different temperature than in the paper... It is roughly in the correct ballpark.

From the same paper, the broadening of the other lines which have the same lower level (but different spin) should be around 4.2 times smaller, i.e., around 0.07 Angstrom.

From the literature, the shifts of the lines should be around 3 to 3.5 times smaller than the broadening, so I would expect a bit less than 0.1 Angstrom shift for the 5 lines that exhibit broadening.

Sending email to Jim, if he is happy with this I will close.

Jim was a bit suspicious that the values are so close to the standard conditions but given that we do not know the physical properties in the lamp he did not think these values are completly ridiculous. As such, I suggest that we close this ticket. We discussed this issue during DRP2D telecom on Aug 02 - I will summarize the issues raised there in the separate ticket.