Ab initio and DFT investigations of intramolecular hydrogen bonding in 1,2-ethanediol

HF and generalized gradient approximation density functional calculations at the BP and B3P levels, supplemented with a series of basis sets of increasing quality, are presented for the lowest energy conformer of 1,2-ethanediol. The critical point of the O … H interaction appears as a weak minimum in a slightly varying low-density electron gas. The 3D analysis shows that at small values of |▿ϱ| an elliptic lens shaped surface appears around this critical point.