Iterative method for finding low-energy conformations based on the model of overlapping spheres: Application to alkanes

A new approximate function for estimation of conformational potential from the excluded volume inside the sphere centered at the geometrical centre of molecule (model of overlapping spheres) is proposed. The value of the func tion was successfully correlated with the conformational energies of six si mple alkanes (from butane to isoheptane). The iterative procedure based on the minimisation of excluded volume is discussed. The method was checked on n-decane and five of its branched derivatives (up to C18H38) The method ap pears to be very efficient in finding the low-energy conformations of norma l alkanes but, for branched molecules, it yielded conformations of higher e nergy in some cases. The method can be regarded as a simple and fast proced ure for finding low-energy conformations.