Paschen series

The Paschen series is the set of emission lines from atomic hydrogen gas, due to electrons descending from an electron shell number n greater than 3 down to n = 3, or the analogous absorption lines when absorbed electromagnetic radiation makes electrons do the opposite. It is one of the hydrogen line series, such as the Lyman series and Balmer series and is named after Friedrich Paschen. Lines:

• 4 -> 3: 1875 nm
• 5 -> 3: 1282 nm
• 6 -> 3: 1094 nm
• 7 -> 3: 1009 nm
• 8 -> 3: 995 nm
• 9 -> 3: 887 nm
• ...
• infinity -> 3: 820 nm

Formula for wavelengths:

1/wavelength = RH ( 1/9 - 1/n² )

• wavelength is the wavelength within the Paschen series.
• R_H is the Rydberg constant for hydrogen, 1.0973731568160 × 10⁷m^-1 = 13.6 eV / hc
• n is the higher electron shell number.
• h - Planck constant.
• c - speed of light in a vacuum.