Ionization energy of atomic hydrogen eV hyperphysics.phy-astr.gsu.edu/hbase/electric/ev.html#c2 http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ev.html University of Georgia: Energies in Electron Volts Ionization energy of atomic hydrogen Energies in electron volts http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ev.html GSU Hyperphysics Ionization energy of atomic hydrogen