Computation of large systems with an economic basis set: a density functional study on proton-bound carboxylic acid clusters

We show that first-principle calculations with an economic basis set can pr edict reliable geometric structures and accurate vibrational frequencies fo r small proton-bound carboxylic acid clusters. This leads to the potential of using limited computational resources to study large molecular systems. Further applications using density functional (DFT) theory on a series of p roton-bound formic and acetic acid clusters have found reasonable evaporati on energies in comparison with experiments. Our DFT calculations have exact ly reproduced the changeover from monomer loss to dimer loss at n = 6 found in an experiment for proton-bound formic acid clusters. (C) 2000 Elsevier Science B.V. All rights reserved.