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Title: Vibrational spectroscopy at interfaces by IR-VIS sum-frequency generation using CLIO FEL

IR-vis sum-frequency generation (SFG) has developed into a versatile technique for probing the vibrational structure of interfaces. To overcome the limited spectral range accessible by benchtop IR lasers, we have developed an SFG spectrometer that makes use of the broad band tuneable infrared beam provided by the CLIO-FEL. We will evaluate the gain in sensitivity of the FEL-SFG spectrometer in comparison to that of benchtop lasers, taking account of the surface damage by laser heating. Thereafter, we review the different research projects undertaken using this facility: (1) The interface selectivity of SFG makes it particularly suitable for probing buried liquid/solid interface. We took advantage of the spectrometer sensitivity to monitor the electrochemical deposition of hydrogen on platinum single crystals at under- and overpotential (2) Because of its sensitivity to the molecular symmetry, SFG allows probing the conformation of self assembled monolayers deposited on metals. We discuss SFG spectra of {omega}(4-nitroanilino)-dodecane adsorbed on polycrystalline gold and silver films; in the 1550 - 900 cm{sup -1} spectral range. (3) We have undertaken a spectroscopic approach for the investigation of polymer films adhesion on glass. Polyurethane/glass interface is investigated in the 2200 - 1600 cin{sup -1} spectral region. (4) The use of themore » CLIO FEL allows probing of the vibrational dynamics of the prominent IR active vibrations between 1500 and 500 cm{sup -1} of fullerene epitaxial films. These modes are modified upon charge transfer from the substrate to the C{sub 60} molecules. Preliminary SFG spectra of C{sub 60}/Ag interface are presented. (5) Site specific detection of CO adsorption and CO + O coadsorption on Pd(111) are studied.« less
Authors:
; ;  [1]
  1. LURE, Orsay (France) [and others
Publication Date:
OSTI Identifier:
238720
Report Number(s):
BNL--61982-Absts.; CONF-9508156--Absts.
ON: DE96002729; TRN: 96:013209
Resource Type:
Conference
Resource Relation:
Conference: 17. international free electron laser conference, New York, NY (United States), 21-25 Aug 1995; Other Information: PBD: [1995]; Related Information: Is Part Of 17th international free electron laser conference and 2nd international FEL users` workshop. Program and abstracts; PB: 300 p.
Research Org:
Brookhaven National Lab., Upton, NY (United States)
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; 43 PARTICLE ACCELERATORS; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; FREE ELECTRON LASERS; LASER SPECTROSCOPY; INFRARED RADIATION; VIBRATIONAL STATES; FREQUENCY CONTROL