%0 Journal Article %A Yusuke Ayato and Takashi Itahashi and Akiko Takatsu and Kenji Kato and Naoki Matsuda %D 2007 %J International Journal of Chemical and Molecular Engineering %B World Academy of Science, Engineering and Technology %I Open Science Index 11, 2007 %T The Concentration Effects for the Adsorption Behavior of Heptyl Viologen Cation Radicals on Indium-Tin-Oxide Electrode Surfaces %U https://publications.waset.org/pdf/12706 %V 11 %X In situ observation of absorption spectral change of heptil viologen cation radical (HV+.) was performed by slab optical waveguide (SOWG) spectroscopy utilizing indium-tin-oxide (ITO) electrodes. Synchronizing with electrochemical techniques, we observed the adsorption process of HV+.on the ITO electrode. In this study, we carried out the ITO-SOWG observations using KBr aqueous solution containing different concentration of HV to investigate the concentration dependent spectral change. A few specific absorption bands, which indicated HV+.existed as both monomer and dimer on ITO electrode surface with a monolayer or a few layers deposition, were observed in UV-visible region. The change in the peak position of the absorption spectra from adsorption species of HV+. were correlated with the concentration of HV as well as the electrode potential. %P 127 - 131