Journal of Molecular Structure. Theochem vol:91 pages:331-344
This paper is concerned with the calculation of the rotational barriers in parahydroxybenzoic acid and polyethylene terephthalate. To compare the calculations with accurate experimental results, experimental gas-phase data of a series of representative aromatic fragments were used to test the theoretical methods employed. AM1 and MNDO-PM3 calculations are presented for these species; ab initio methods were tested by means of extensive calculations on benzaldehyde.