D. Iwaneko and L. Landau

“ For example, the spectrum of helium cannot be constructed from antisymmetric eigenfunctions (in the sense of three quantum numbers for each electron) , but rather one is forced to use symmetric ones as well (Parahelium) . [4] In all cases where the electron spin is not considered, Pauli's principle does not apply; it is therefore of no importance for the general problems of statistics.
We therefore believe that Dirac's justification of "antisymmetric" statistics is not sound; a selection of the solutions is also in contradiction with the fundamentals of wave mechanics. ”

“ Ehrenfest's "diagonal requirement" is therefore untenable; it contradicts the elementary explanations of wave mechanics. For example, in the case of hydrogen atoms, (at the coordinate origin!) is not always zero. Aren't electrons and protons more "penetrable" than molecules?
The situation becomes even clearer if we apply Ehrenfest's considerations to the case of two molecules with different masses. The general solution of Schrödinger's equation is then
,
where , and , represent the eigenfunctions and eigenvalues of the two molecules, respectively. ”