Ab initio Study of the Structure of the Molecular Forms of C3H4O2

Abstract

The geometrical parameters, force fields, and vibration frequencies were calculated by the ab initio SCF MO LCAO technique using extensive basis sets of Cartesian Gaussian functions for a number of structural isomers of the C₃H₄O₂ molecule. The relative energies of all the isomers were refined in terms of second-order Möller–Plesset (MP2) perturbation theory including electron correlation. For the most energetically favorable forms of the C₃H₄O₂ molecule, geometry optimization was fulfilled in the MP2 approximation. For the main conformer, β-hydroxypropenal, possessing a chelate OCCCO fragment, the data are compared with the experimental and theoretical data available in the literature. The MP2 calculated internuclear distances and bond angles are in good agreement with the experimental values. For each form of the C₃H₄O₂ molecule, the geometrical and electronic structure is analyzed. It is shown that the presence of an intramolecular hydrogen bond is the characteristic feature of the structure of the isomers and an additional stabilizing factor.