Double- or single-well potential for GSIPT in 1-hydroxy-2-acetonaphthone?

Potential energy surfaces for intramolecular proton transfer of ground state (GSIPT) of 2-hydroxyacetophenone and 1-hydroxy-2-acetonaphthone have been calculated by using MP2 and B3LYP methods. The main results are as follows. (a) Intramolecular proton transfer shows an strong coupling with the distances between the oxygen atoms which support the intramolecular hydrogen-bonding. (b) The correlated GSIPT curves of both compounds have a single minimum in the ground state, corresponding to the enol form. (c) This previous coclusion does not support the assumption made by Douhal et al. on the HAN GSIPT curve is a double well potential curve.