Concepts vs. Accuracy??

In response to David Bernhold's thoughts, a quote from Levine's 'classical'
 QUANTUM CHEMISTRY:
        Approximation of the helium ground-state wave function as a product
 of hydrogenlike 1s orbitals with effective nuclear charge zeta [...] provides
 a simple physical picture that is in accord with the usual chemical concepts;
 however, this function does not give a very accurate value for the energy.
 When we use a function like [...] with a hundred or so terms, we get an
 extremely accurate wave function and energy, but we lose the simple physical
 interpretation.  This is a general occurrence in quantum chemistry; "the
 more accurate the calculations become the more the concepts tend to vanish
 into thin air."[6]
     [6] R. S. Mulliken, J. Chem. Phys., 43, s2 (1965).
                                Levin, pg. 209
       Jan Jensen (NU145752 ( ( at ) ) NDSUVM1.EDU)
       Dept. of Chemistry
       North Dakota State University
       Fargo, ND 58105
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