Study of the electronic structure of molecules. IV. All-electron SCF wavefunction for the ground state of pyridine

An all-electron SCF LCAO MO wavefunction is presented for the ground state of the pyridine molecule. The basis set is built with Gaussian functions and all many-center integrals are accurately computed in this work. The lowest π orbital is below the second-lowest σ orbital; the lone pair on nitrogen is partly delocalized on the neighboring carbon atoms, but retains 1.41 electrons in the sp hybrid on the nitrogen nucleus.