The attractive rotational barrier in nitrosomethane

An ab initio LCAO MO SCF calculation has been carried out on staggered and eclipsed forms of nitrosomethane. The rotational barrier found (1.05 kcal/mole) is in excellent agreement with the experimental value (1.10 kcal/mole). An energy component analysis shows nitrosomethane to be an attractive dominant barrier, thereby unequivocally demonstrating the possibility of a small scale, attractive covalent force as the controlling effect in some three fold barriers.