Electric and magnetic fields generated by the nucleus

With given nuclear charge density distribution p(r) and nuclear current density distribution j r), we can now obtain all quantities required to describe the resulting electric and magnetic fields from basic relations of the theory of electromagnetism [11]. 

The resulting electrostatic potential can be obtained from the charge density distribution via the Poisson integral, 

The electric field, generated by the nuclear charge density distribution, is obtainable from the electrostatic potential or from the charge density distribution as 

For application in the quantum mechanical problem of determining the atomic or molecular electronic structure we need the potential energy function V r) = often simply called the potential for brevity. 

This function always enters the quantum mechanical electronic structure problem, regardless whether it is treated non-relativistically, based on the Schrddinger equation, or relativistically, based on the Dirac equation. 

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