Shape of the lead-phthalocyanine (PbPc) molecule and the field-induced switching effect in monoclinic PbPc

Abstract We present model calculations of the geometrical structure of Lead-Phthalocyanine (PbPc) molecules. The central part of a single molecule is treated by a LCAO-X α cluster method. A minimum value of the sum of orbital energies corresponds to a nearly planar molecule. Molecular stacks encountered in the monoclinic crystalline phase are described by a simple electrostatic linear chain model. Properly chosen molecular units of this chain exhibit a metastable conformation and reflect within the chain the shuttle-cock shape known from x-ray diffraction.