I'm interested in the spectra of gas discharge tubes. Taking neon as an example, when I look up on NIST the spectra for neon, I find excitation states up to Ne IX. Where do I find/how do I work out which excitation states are predominate in a neon light? Is it voltage- or current-dependent, or depending on transition probabilities somehow? For context, I studied physics but lack some of the finer details that chemists have when it comes to electron configurations.
Ideally I'd like an answer that applies to elements other than neon, as all of the noble gases and a couple of others are common inside gas discharge tubes.