Madelung
Madelung is a surname associated with several concepts in physics and chemistry, most notably in solid-state physics and quantum mechanics. The term appears in a number of results named after German physicists such as Erwin Madelung and Otfried Madelung, who contributed to ionic crystals, quantum hydrodynamics, and atomic structure.
One prominent usage is the Madelung constant, a dimensionless lattice sum that characterizes the electrostatic energy
Another use is the Madelung transformation, which expresses the quantum mechanical wave function in polar form, ψ
Madelung's rule, also called the diagonal rule, governs the order in which atomic orbitals are filled by