What is the origin of the strong red line in the sodium emission spectrum?

[Bob S]

Here is a high pressure sodium spectrum from www.umd.edu[/url] in the first attachment, and a listing of visible sodium lines from [url]www.nist.gov[/URL] in the second attachment. In the sodium spectrum, a triplet of red lines is visible. In the NIST table, a quartet of red lines near 6500 Angstroms from ionized sodium are shown. Three of the red lines in the Table are spaced at about 15 Angstroms, and the fourth is only 1.7 Angstroms away, and is probably not resolved. The three red lines visible in the spectrum are probably the three lines listed in the Table.

Bob S

 

[Vanadium 50]

Bob, that was the wrong explanation a year ago when you first posted it, and it's the wrong explanation now. He's looking for strong lines, and the lines you have posted are weak.

High pressure sodium is irrelevant. He says he's studying the D-lines, and you have pressure broadening in high pressure sodium that makes this impossible - indeed, there you can have emission in the red: the D-lines can get that broad.

Sodium does not have any strong red lines. However, a sodium vapor tube can have all sorts of other things in it. Mercury, argon and neon are all commonly present. Before trying to figure out why an element without strong lines in the red somehow has strong lines in the red, wouldn't it make sense to ask what exactly is in the tube? And indeed, wasn't the reason spectroscopy was developed to answer the question "which elements am I looking at"?