Absorption spectroscopy 12 Polarization modulation infrared reflection absorption spectroscopy 12 Self assembled monolayers 10 Gold 8 Photoelectron spectroscopy 6 Scanning tunneling microscopy 6 Copper 4 Covalently bonded 4 Cyclic voltammetry 4 Density functional theory 4 Electrochemistry 4 Electronic structure 4 Molecular orbitals 4 Monolayers 4 Reduction 4 Surface normals 4 article 4 chemistry 4 gold 4 6-mercaptopurine (6MP) 2 Absorption 2 Adsorption 2 Alkanethiolates 2 Alkanethiols 2 Au surfaces 2 Au(1 1 1 ) 2 Au(111) surfaces 2 Biomedical applications 2 Bipyridine ligands 2 Carboxylic acids 2