hydrogenserien
Hydrogenserien refers to groups of spectral lines in hydrogen that arise when an electron transitions from a higher energy level n2 to a fixed lower level n1. Each series is defined by its lower level, with n1 = 1 giving the Lyman series (ultraviolet), n1 = 2 the Balmer series (visible), n1 = 3 the Paschen series (infrared), n1 = 4 the Brackett series (infrared), n1 = 5 the Pfund series (infrared), and n1 = 6 the Humphreys series (infrared), among others. The lines converge to a series limit as n2 increases without bound.
The lines can be described by the Rydberg formula for hydrogen: 1/λ = R∞ (1/n1^2 − 1/n2^2), where
Historically, the Balmer series (n1 = 2) was described empirically in 1885, the Lyman series (n1 = 1)
The hydrogenserien are fundamental in spectroscopy and astrophysics, enabling measurements of composition, temperature, density, and motion