Articles you may be interested inIdentifying site-dependent effects of an extra Co atom on electronic states of single Co-phthalocyanine molecule Abstract. In order to experimentally analyze the influence of a small symmetry break on the degeneracy of discrete energy levels we have carried out STM/STS investigations on triphenylphosphine molecules (P(C 6 H 5 ) 3 ) adsorbed to Au(111) surfaces. The measurements were performed with a variable-temperature UHV-STM which was operated at 6.5 K. From the experimentally obtained I(V) data the energy-level distribution is derived for individual molecules and a symmetryreduction-induced decrease of the level degeneracy can be observed in detail and compared with former results.