On the Correct Formulation of Pauli's Exclusion Principle

Abstract

PAULI'S ‘Exclusion Principle’ applied to the simplest case of the two-electron or two-proton system (helium atom, hydrogen molecule) is usually stated as follows: if the electrons (or protons) are parallel, that is, if their spins point in the same direction, their eigenfunction must be antisymmetrical with respect to the co-ordinates; if the electrons (or protons) are antiparallel, that is, pointing in opposite directions, their eigenfunction must be symmetrical.