PHOTOEMISSION FROM LONG CHAIN ALKANES ADSORBED ON A METAL SURFACE AND THE ELECTRONIC STRUCTURE OF TRANS-POLYETHYLENE (–CH₂–)n

The adsorption geometry of n-alkanes on the surface of noble metals (Cu, Au) has been investigated by ultraviolet photoemission spectroscopy (UPS) in order to resolve apparent inconsistencies with regard to the orientation of the C–C–C plane relative to the surface. Measurements were carried out for octane ( C 8 H 18 ), hexatriacontane ( C 36 H 74 ) and triacontanoic acid ( C 29 H 59 COOH ) on Au (111) and Cu (111). Analysis of the data requires a detailed symmetry analysis of the electronic structure of trans-polyethylene (– CH 2 –), which is also presented and yields an orientation of the C–C–C plane parallel to the surface for all molecules.