Surface Effect of Alumina on the First Electronic Transition of Liquid Water Studied by Far-Ultraviolet Spectroscopy.
The first electronic transition (Ã ← X̃) of liquid water (H2O and D2O) on an α-alumina substrate was studied using variable angle attenuated total reflection far-ultraviolet (VA-ATR-FUV) spectroscopy in the wavelength region 140-180 nm (8.86-6.89 eV). A variation in the penetration depth of the evanescent wave of a probe light (25-19 nm) directly determined individual FUV spectra associated with bulk water (distance from the alumina surface >2 nm) and interfacial water (<2 nm). We found that the Ã ← X̃ band of the interfacial water was markedly blue-shifted and red-tailed relative to the bulk water. The electronic state difference of the interfacial water from the bulk water mainly arose from the hydrogen-bond structure and energy affected by the alumina surface.
†Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.
Takeyoshi
T
Goto
‡National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-8642, Japan.
Akifumi
A
Ikehata
§Department of Chemistry, School of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
Yusuke
Y
Morisawa
†Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.
Yukihiro
Y
Ozaki
attenuated total reflection (ATR); far-ultraviolet (FUV); hydrogen bond; interfacial water; isotope effect