Molecular orbital calculations on distorted hydrogen bonds in the water dimer

Abstract

CNDO/2 MO calculations have been carried out to investigate the effect of distortions of the hydrogen bond in the open water dimer. Linear dimers of water are more stable when the O–H vector is not directed towards the lonepair orbital of the donor oxygen atom, the stability being maximum when the hydrogen is in between the two lonepair orbitals. Bending the hydrogen bond in the water dimer markedly decreases hydrogen-bond energy and increases the dimer energy when the angle of bend is greater than ca. 30°.