Analysis of Water and Aqueous Solutions by Far Ultraviolet Spectroscopy

In the far ultraviolet (FUV) region (120-200 nm), absorption bands due to transitions of outer orbital electrons have been observed. These absorption coefficients are so large that the uses of FUV spectroscopy had been limited involving applications to gases and reflectance on solid surfaces. We developed FUV spectroscopy method designed for the purpose of measuring of liquid by using attenuated total reflection (ATR) with nitrogen gas purge. The ATR-FUV spectrometer reveals the features of the FUV spectra of liquid samples. The first electronic transition band of water, which shows systematic change with the state of hydrogen bonding, had become a good candidate of this system. This paper describes the ATR-FUV analysis of aqueous solutions and the related basic properties of the UV and FUV spectra of water.