New Application of Far-ultraviolet Spectroscopy

Recently, spectroscopy and photonics in the far-ultraviolet (FUV) region (120 - 200 nm region) have been a matter of great attention because of rapid development of sensitive instruments in this region and an increase in the possible applications. In the present work the state-of-the-art of progress in FUV spectroscopy of the liquids and solids, which are concerned with various valence electronic transitions including sigma, n, and pi electrons, were outlined. FUV spectroscopy is rich in information about the electronic structure and transitions of a molecule, but the absorptivity is very high for liquid and solid states in the FUV region. Thus, spectral measurements for condensed matter in this region were difficult. To overcome this difficulty we introduced an attenuated total reflection (ATR) technique to the FUV region. ATR-FUV spectroscopy has paved a new avenue for condensed-matter FUV spectroscopy. This article demonstrates that FUV holds considerable promise in various fields of research from basic science, such as studies of electronic structure of molecules and those of hydrogen bonding, hydration, and adsorption of water, to material researche, such as polymers, inorganic semiconductors, and ionic liquids.