Ab Initio Calculations on Large Molecules Using Molecular Fragments. Oxygen-Containing Molecules

An ab initio procedure for the investigation of large molecules is applied to a series of oxygen-containing molecules. Prototype molecules used to characterize the procedure include H2O, H2O2, CH3OH, CH3OCH3, furan, H2CO, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, and HCOOCH3. The method is found to provide interesting and useful information concerning electronic structure and molecular geometry in spite of the restricted sets of basis orbitals employed. When possible, comparisions are made with other theoretical results as well as experimental values.