On the Heats of Formation of Alkanes

a broad diverse test set of alkanes and cycloalkanes previously studied with mm4 calculations has had the heats of formation calculated by several different quantum mechanical methods: hartree-fock, mp2, and mp4, and also by b3lyp and b3lyp + dispersion energy. overall, three computational methods (mm4, mp4, and b3lyp + dispersion) yield results that are generally of experimental accuracy. these results are analyzed and compared in some detail.