Pseudospectral calculation of the gas-phase acidities of aliphatic alcohols

The acidity of aliphatic alcohols in gas phase is reinvestigated with the a im at establishing the simplest, yet reliable, level of description to be u sed for the solute in a solution-phase acidity calculation. It is shown tha t a procedure which includes only the differential correlation effects aris ing from the O-H bond being broken and its first neighbor bonds can generat e reliable results for a comparative study of gas-phase and solution-phase acidities, thus considerably reducing the computational effort to obtain su ch a property in solution. Preliminary pK(a) results for alcohols in water solution show a reasonable agreement with the available experimental data. Also, the fact that the pseudospectral formulation of both Hartree-Fock (HF ) and the local Moller-Plesset second-order perturbation theory (L-MP2) hav e been used, makes the procedure applicable to much larger molecules. (C) 1 999 John Wiley & Sons, Inc.