Molecular orbital studies of interaction force constants in dicarbonyl compounds

Abstract

Molecular orbital calculations are used to evaluate interaction force constants in biacetyl, acetic anhydride and acetyl acetone. Normal coordinate analyses are performed for these three molecules utilizing the MO-calculated interaction force constants. Analogous normal coordinate calculations are also carried out within the framework of the simple valence force field, in which all interaction force constants are neglected. It is shown that the former calculations reproduce the experimental carbonyl spacings satisfactorily; whereas the latter (SVFF) calculations are grossly in error.