Accession Number : ADA193748

Title :   Interfacial Infrared Vibrational Spectroscopy.

Descriptive Note : Technical rept.,

Corporate Author : UTAH UNIV SALT LAKE CITY DEPT OF CHEMISTRY

Personal Author(s) : Pons, Stanley ; Foley, John K ; Russell, Joel ; Seversen, Mark

PDF Url : ADA193748

Report Date : 30 Jul 1986

Pagination or Media Count : 78

Abstract : Vibrational spectra of species on or near metal surfaces are subject to a unique surface selection rule due to the physics of reflection of radiation from a highly conducting surface. As shown in Fig. 1, s-polarized radiation (electric vector perpendicular to the plane of incidence) at all angles of incidence undergoes a phase shift close to 180 C. P-polarized radiation (electronic vector in plane of incidence) has a phase change upon reflection which varies with the angle of incidence as also shown in Fig. 1. Light reflected from a metal surface combines with the incident light to form a standing wave electric field whose intensity is shown in Fig. 2. The mechanism for absorption of infrared radiation requires a coupling of the electric field with a molecular vibration. Since the intensity of the standing wave electric field parallel to the surface is near zero, only those modes of a species near the metal surface which produce a fluctuation in the dipole moment with component normal to the surface can absorb energy.

Descriptors :   *INFRARED SPECTROSCOPY, *MOLECULAR VIBRATION, *VIBRATIONAL SPECTRA, *SURFACE CHEMISTRY, *ELECTROCHEMISTRY, ANGLE OF INCIDENCE, DIPOLE MOMENTS, ELECTRIC FIELDS, INFRARED RADIATION, INTERFACES, METALS, PHASE SHIFT, PHASE TRANSFORMATIONS, RADIATION ABSORPTION, SPECTROSCOPY, STANDING WAVES, SURFACES, RAMAN SPECTRA

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE