 Balmer series

The Balmer series consists of hydrogen transitions terminating at principal quantum number $n=2$. Its emission wavelengths obey $1/\lambda =R_H(1/4-1/n_i^2)$ for $n_i=3,4,\dots$, a special case of the Rydberg formula.

The first transitions fall in the visible part of the electromagnetic spectrum, while the high-level lines converge toward a shorter-wavelength limit with ${\lambda }_{\lim }=4/R_H$. A hydrogen discharge observed through a spectroscope shows separated lines rather than a smooth continuum because the atomic energy differences are discrete.

The same level separations can produce absorption when atoms initially occupy the lower state. Temperature, excitation and the number of atoms in that state affect line strength; a wavelength formula alone does not predict the observed relative intensities.

The Balmer series is a set of spectral lines corresponding to the transitions of electrons in hydrogen atoms from higher energy levels to the second energy level (n = 2). This series is part of the hydrogen emission spectrum and consists of visible light wavelengths.