Fermi-sea zero-order wavefunctions

It is such types of heavy mixing that, together with additional evidence (see following sections), led to the proposal of opfimizing fhe quantitative description of electronic structures by computing appropriately chosen multiconfigurational Fermi-sea zero-order wavefunctions (Sections 3 and 8). 

The case of fhe ground state, S, was already discussed in Section 5, with numerical results for different values of Z. Bofh fhe H-F sea and the Fermi-sea zero-order wavefunctions are described by a superposition of fhe ls 2s IS and W2p SACs. 

Furthermore, and this is important for fhe inferprefafion of the bonding in Be2 to be discussed below, the results (17-20) show that primarily the state D and to a lesser degree the state carry with them a significant d — wave component in their Fermi-sea zero-order wavefunctions. This means that such orbitals should also be considered in the self-consistent, zero-order description of molecules containing Be. 

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