The Electronic Structure of Water: Pulling Rabbit-Ears out of a Wave Function

The electronic structure of water is typically thought of exhibiting lone-pairs of electrons, described by some as "rabbit-ears'". This is not the universal view, and does not mesh with an interpretation based on the one-electron wavefunctions which emerge from molecular orbital theory. Here we show, by analysing the antisymmetrized wavefunction (Slater determinant) rather than the Hartree product, that the water wavefunction indeed exhibits equivalent lone pairs. The observed photoelectron spectrum is reconciled with this view in terms of a relaxation of this structure upon the loss of an electron. It is therefore shown that the lone-pair viewpoint is completely consistent with both the experimental results and the calculated wavefunction.