Abstract: | Different schemes are explored for the calculation of the proton transfer process in the hydrogen bonded cation [CH3OH · H · NH3]+. Results from ab-initio calculations with the STO-3G, 3-21G and 4-31G basis sets, are compared in search for an efficient reliable scheme to study the potential energy curves for the proton transfer. The curve constructed from the lowest energies calculated with the frozen optimized geometries of the two possible pairs of proton donor and acceptor fragments, (i.e., CH3OH/NH3 and CH3OH/NH) is in good agreement with that obtained when all the fragments of the hydrogen bonded complex are completely optimized simultaneously. |