INFRARED SYNCHROTRON RADIATION INSTRUMENTATION AND APPLICATIONS

Infrared synchrotron radiation (IRSR) is a blossoming field which has three working beamlines, U4IR at the National Synchrotron Light Source, Brookhaven National Laboratory, USA, and two at the Institute of Molecular Sciences in Okasaki, Japan, with extensive research projects. There are also several new beamlines in the planning and development stages, both in the United States and abroad. IRSR offers a unique way to access the far infrared (30-mu-m to approximately 1 mm), which is a notoriously difficult region to work in. In particular, experiments that demand high brightness are well suited to IRSR just as they are in the X-ray region. The central issue in all of the experiments to date has been good signal to noise, which has been the focus of the instrumentation improvements at the U4IR beamline. A commercial Fourier transform instrument was the chosen spectrometer. Then modifications were made in order to expand the usable region of the existing experiments, in both the far and near infrared. As an example of the performance of this beamline, I will focus on the reflection absorption spectroscopy results for adsorbates on clean surfaces in ultrahigh vacuum.