The seventh series of atomic hydrogen was first demonstrated experimentally at infrared wavelengths in 1972 by Peter Hansen and John Strong at the University of Massachusetts Amherst.OverviewThe of atomic has been divided into a number of spectral series, with wavelengths given by the. These observed spectral lines are due to the making between. A hydrogen atom consists of a nucleus and an electron orbiting around it. The between the electron and the nuclear leads to a set of for the electron, each with its own ene. The energy differences between levels in the Bohr model, and hence the wavelengths of emitted or absorbed photons, is given by the Rydberg formula: where • Z.