Polarization approximation is illegal

the polarization approximation zero-order wave function a,o b,o ill be deprived of the privilege of being the unperturbed function in a perturbation theory. Since it will still play an important role in the theory, let us denote it by 

The polarization approximation seems to have (at hrst glimpse) a very strong foundation, because at long intermolecular distances R, the zero-order energy is close to the exact one. The trouble is, however, that a similai statement is not true for the zero-order wave function and the exact wave-function at any intermolecular distance (even at infinity). 

Let us take an example of two ground-state hydrogen atoms. The polarization approximation zero-order wave function 

This function is neither symmetric (since 1)), nor antisymmetric (since 2) — p 2,1)), and therefore is illegal and in 

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Polarization Approximation Is Illegal Constructing a Symmetry Adapted Function The Perturbation is Always Large in Polarization Approximation Iterative Scheme of SAPT Symmetry Forcing... 

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