Knowledge Bank

A molecular vibrational analysis was carried out for furan and pyrrole and some of their deuterium and methyl derivatives. To insure convergence in the least-squares adjustment of the force constants, interaction constants were assumed transferable between the furan and pyrrole rings, and observed wavenumbers of the two compounds and their derivatives were used in a single adjustment. The vibrational assignments obtained for the parent molecules confirmed the accepted assignment for furan and cleared up uncertainties in the assignment for pyrrole.