A. Léger

Evidence from inelastic electron tunnelling spectroscopy for vibrational mode reassignments in simple aliphatic carboxylate ions

Abstract Tunnelling studies of the vibrational spectra of formate- and acetate-, including 18 O-enriched acetate-, anions adsorbed on plasma-grown aluminium and magnesium oxide surfaces show that the CO 2 − symmetric stretch mode can be clearly distinguished from the CH modes in the same region of the spectra. This CO 2 − mode of the formate ion is at 1456 cm −1 on aluminium oxide and at 1348 cm −1 on magnesium oxide; for the acetate ion the corresponding values are 1463 and 1445 cm −1

Interaction of acetylcholine and β-methylacethylcholine with aluminium oxide surface studied by inelastic electron tunneling spectrometry

Summary Inelastic Election Tunneling Spectrometry (IETS) yielded useful information on the interaction of Acetylcholine and its analog β-Methylacetylcholine with an alumina surface. The spectra obtained are discussed in comparison with infrared and Raman spectra of the same molecules in solid state and in aqueous solutions studied previously by the authors. It is shown that under certain conditions AL 2 O 3 catalyses the hydrolysis of molecules as does the Acetylcho-Line-esterase enzyme on the postsynaptic membrane or a basic aqueous medium with a pH greater than 9.

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.