Theoretical study of small water clusters of dicarboxylic acids

COMP 429

Fu-Ming Tao, ftao@fullerton.edu, Department of Chemistry and Biochemistry, California State University, Fullerton, Fullerton, CA 92834
Density functional theory and ab initio molecular orbital theory are used to study the molecular clusters of four simple dicarboxylic acids (oxalic, malonic, succinic, and glutaric acids) with water. The equilibrium structures, binding energies, harmonic vibrational frequencies, and infrared intensities of the clusters in various conformations are calculated using the B3LYP and MP2 methods with the 6-311++G** and aug-cc-pVDZ basis sets. Hydrogen bond interactions of the acids with water molecules play a dominating role in the geometrical conformations of the acids within the clusters. All stable conformations of the clusters are found to be strongly hydrogen-bonded, and. The structures, stabilities, and other molecular properties of the clusters are discussed along with the implications in atmospheric chemistry.