Experimental study of relative intensities in inelastic electron tunneling spectroscopy (I.E.T.S.)

Abstract We present an experimental study of the relative intensities in inelastic tunneling spectra of formic and acetic acid chemisorbed on alumina. The theoretical framework is given by the simplest theory of tunneling intensities, the theory of Scalapino and Marcus. The comparison between our experimental results and the predictions of this theory provides evidence for an important discrepancy in the relative intensities in the spectrum of a given molecule. This disagreement is only partially resolved by considering the influence of the counter-electrode of the junction on the tunneling intensities. So, on the basis of an alternative derivation of the results of the theory of Scalapino and Marcus, we discuss to what extent it can be applied to the interpretation of tunneling spectra.