New molecular mechanics (MM2) parameters for ketones and aldehydes

The parameter set in MM2 has been changed to permit more accurate calculations on carbonyl compounds, taking into account ab initio calculations reported recently by Wiberg on 2-butanone and other data which have become available since the original formulation. Several major problems regarding carbonyl compound con­ formations and energies have been addressed, and the results are uniformly better than they were with MM2(77).