THE ORIENTATION OF CHLOROPHYLL AND BACTERIOCHLOROPHYLL MOLECULES IN AN ORIENTED LECITHIN MULTILAYER

Abstract— Chlorophyll a and b and bacteriochlorophyll a have been incorporated in an oriented phospholipid multilayer. The orientation of the chlorophyll molecules in this layer has been measured by polarization spectroscopy. Formulas are given expressing the dichroic ratio R as a function of the angle of tilt θ between the molecule and the plane of the multilayer and the angle μ between this plane and the transition dipole moment measured in the plane of the molecule. The possibility of overlapping bands of mutually perpendicular polarization has been taken into account. Analysis of the experimental results gives the angles θ and μ as well as an estimate for the fraction of polarization of some bands along the dihydro axis in the plane of the chlorophyll molecule.