Editing Openai/6897769e-4ee4-800f-aba5-69cca34f701c (section)

=== - “More interactive with the atom” depends on temperature, ionization state, density and excitation mechanism. For example: - He II 468.6 nm is a recombination line of singly-ionized helium and requires much higher temperatures/ionization than H I Balmer lines. - Fe XIV 530.3 nm is a coronal (forbidden) line that appears in very hot, low-density coronal plasmas. - Na D lines are resonance transitions that are strong in many cool atomic environments. Which line dominates depends on the plasma’s physical state — there isn’t a universal “more interactive” line across all conditions. For any given physical plasma you must use the plasma’s excitation conditions to pick the correct set of dominant lines (and intensities). ===