Torsion energy profiles and force fields derived from ab initio calculations for simulations of hydrocarbon-fluorocarbon diblocks and perfluoroalkylbromides

Torsional potential energy profiles for two classes of substituted perfluoroalkanes-hydrocarbon-fluorocarbon diblocks and 1-bromoperfluorolakes-are calculated ab initio by incorporating correlation effects and using flexible basis sets. Dihedral angle functions for use in molecular simulations are derived from the quantum mechanical profiles.