Far-infrared Synchrotron Radiation Research Articles

Synchrotron-based far-infrared spectroscopy of furan: Rotational analysis of the ν14, ν11, ν18 and ν19 vibrational levels

Four vibrational levels of the five-membered ring molecule furan (C 4H 4O) have been rotationally analyzed from far-infrared Fourier transform spectra obtained at the Canadian Light Source synchrotron. We found that the low-lying ν 14 and ν 11 levels at 602.9 and 599.6 cm −1 interact through a second-order Coriolis resonance. This perturbation was characterized through a coupled analysis of the ν 14 and ν 18 fundamental spectra and the ν 18– ν 11 band. The ν 19 fundamental spectrum was analyzed as well, and the data for all observed bands were combined with previously reported microwave transitions to produce the final fit. The spectra are an excellent demonstration of the high quality of data that can be obtained when far-infrared synchrotron radiation is used as the radiation source in Fourier transform spectroscopy experiments.

High-resolution far-infrared spectroscopy at NSLS beamline U12IR

A Bruker model IFS 125HR Fourier transform interferometer has been installed and its performance tested using high-brightness, far-infrared synchrotron radiation. Results of absorption measurements for the rotational modes of water vapor demonstrate a nearly 10-fold improvement in signal-to-noise when compared with the instrument’s internal high-pressure Hg arc lamp source.

Studies of intermolecular vibrations in hydrogen-bonded molecular complexes for the gas phase using a synchrotron radiation source

An electron storage ring acts as an approximate point source in the far-infrared spectral region with a much greater intensity than provided by conventional black body radiators. Far-infrared synchrotron radiation is therefore suitable for high-resolution spectroscopic measurements of low-frequency vibrations for metastable molecules such as the intermolecular vibrational modes of hydrogen-bonded molecular complexes. The present paper describes the use of synchrotron radiation from the MAX-I electron storage ring, Lund, Sweden, for far-infrared measurements of several hydrogen-bonded molecular complexes in the gas phase.

Far-infrared synchrotron radiation for in situ studies of the electrochemical interface

In the last decade there have been many advances in in situ spectroscopic methods to study the electrode/electrolyte interface [1]. Such studies have begun to provide the molecular data required to construct a microscopic model of the electrochemical interface. Mid-infrared (750-4000 cm -~) experiments have provided information regarding the identity and orientation of adsorbed molecules and evidence of the strength of the electric field at the electrochemical interface, the electrochemical Stark effect [2]. The vibrations of the metal-adsorbate bond, however, are of low frequency, in the far-infrared (< 750 cm-1). Thus, to obtain direct information on the metal-adsorbate bond and to probe the electric field strength within the first 1-2 ,~ of the metal surface in situ far-infrared studies are required. To date there has been only one in situ far-infrared investigation of the electrochemical interface published [3]. This study by Li et al. used a thermal far-infrared source to study the deposition of lithium on gold. The acquisition