THE NATURE OF BOND ORBITALS AND THE ORIGIN OF POTENTIAL BARRIERS TO INTERNAL ROTATION IN MOLECULES.

摘要: Twenty years ago Kemp and Pitzer(1) discovered that the relative rotation of two methyl groups about carbon-carbon bond in ethane is not completely free but restricted by a potential barrier 3.0 kcal/mole high, with three maxima minima complete rotation, corresponding to trigonal symmetry groups. It was soon found single bonds many molecules, experimental values for height have been obtained analysis thermodynamic quantities (entropy, heat capacity) especially methods microwave spectroscopy.