Emission Spectra

When an atom absorbs energy, the electrons become excited and move to a higher energy level. As the electrons relax down to either a lower energy state or to the ground state, the excess energy is released as a photon.

The wavelength of the absorbed and emitted light depends on the difference between the high and low energy levels. High energy emitted light results from electrons relaxing from a higher energy level, and low energy emitted light results from electrons relaxing from a lower energy level.

An emission spectrum is a measure of emitted radiation across a range of wavelengths. With pure elemental species, the emission behavior appears as lines of specific wavelengths rather than a broad spectrum. This is the emission spectrum for hydrogen.

The set of spectral lines in the visible light region is known as the Balmer series. It occurs when electrons transition from an energy level higher than n = 3 back down to n = 2.

The visible light spectrum appears as spectral lines at 410, 434, 486, and 656 nm, which correspond to energy level transitions from n = 3, 4, 5, and 6, respectively, to n = 2. Additional spectral lines can be measured outside of the visible range, such as the