Accession Number : ADA188511

Title :   In-Situ Vibrational Spectroscopy of Specifically Adsorbed Azide on Silver Electrodes.

Descriptive Note : Technical rept.,

Corporate Author : IBM RESEARCH DIV SAN JOSE CALIF

Personal Author(s) : Samant, M G ; Viswanathan, R ; Seki, H ; Bagus, P S ; Nelin, C J

PDF Url : ADA188511

Report Date : Nov 1987

Pagination or Media Count : 30

Abstract : In-situ infrared vibrational spectra of azide ions specifically adsorbed on polycrystalline silver electrodes immersed in aqueous electrolytes of composition 1 to 30 mM azide and 0.1M perchlorate are reported for the potential range (I)0.25 to 0V versus Ag/AgCl (3M KC1). Adsorbed azide was not detected spectroscopically between 0V and -0.9V, a range (II) known from differential capacitance measurements to allow adsorption onto the silver electrodes. These experimental observations have been interpreted with the help of ab-initio calculations of the vibrational frequencies of AgN30 and AgN3- for two configurations with C and C2v symmetries representing primitive models for azide absorbed with its configuration axis perpendicular and parallel to the electrode surface, respectively. Besides the charge states specified, calculations are also reported for static applied fields along the symmetry axis. Taken together, the experiments and calculations support a model in which azide adsorbs oriented perpendicular to the surface at the higher surface concentrations induced by the more positive potentials of range I, and is adsorbed with long axis parallel to the surface in potential range II. Keywords: Infrared, Vibrational spectroscopy, Electrochemistry, Silver, Azide.

Descriptors :   *AZIDES, *ELECTRODES, *INFRARED SPECTROSCOPY, ADSORPTION, CAPACITANCE, ELECTROCHEMISTRY, ELECTROLYTES, INFRARED SPECTRA, IONS, LIQUIDS, MEASUREMENT, POLYCRYSTALLINE, SILVER, SILVER ALLOYS, SURFACES, VIBRATIONAL SPECTRA, POTENTIAL ENERGY, FOURIER TRANSFORMATION, INFRARED SPECTROSCOPY

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE