DENSITY-FUNCTIONAL STUDIES ON HYDROGEN-BONDED COMPLEXES

Results of density functional calculations will be reported on a variety of hydrogen-bonded complexes, ranging from weak to strong hydrogen bonds. The charged bimolecular NH3-NH4+ complex and the dimers of water and methanol were investigated using a local approximation of the exchange-correlation potential and two different nonlocal potentials with gradient corrections. In the case of the water dimers, the dependence of the results on the extension of the atomic basis set has also been investigated. The equilibrium structures of all complexes have been determined. Dipole moments, hydrogen-bond lengths, and hydrogen-bonding energies, calculated with corrections for the basis-set superposition error using the counterpoise method, have been found to agree well with the corresponding experimental results. (C) 1994 John Wiley & Sons, Inc.