title: Effect of cations on absorption bands of first electronic transition of liquid water.
abstract: The effect of cations (Li(+), Na(+), K(+), Rb(+), and Cs(+)) on the first electronic transition (A <-- X) of liquid water was investigated by attenuated total reflection far ultraviolet spectroscopy. To negate the effect of anions, aqueous solutions of 1 M alkali metal nitrates and bromides were compared at a temperature of 25 degrees C. It is found that the peak energy of the A <-- X band of water, which shows a marked red shift with decreasing hydrogen-bond strength, decreases with increasing cation size. The peak energies of the A <-- X band can be approximated by a linear function of the inverse of the ionic radii of the alkali metal cations, which indicates (according to the Born equation) that the first electronic transition of water is characterized by the solvation energy of the cations.
authors.affiliation: Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan. ikehata@affrc.go.jp
authors.forename: Akifumi
authors.initials: A
authors.lastname: Ikehata
authors.forename: Motoki
authors.initials: M
authors.lastname: Mitsuoka
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Morisawa
authors.forename: Naomi
authors.initials: N
authors.lastname: Kariyama
authors.forename: Noboru
authors.initials: N
authors.lastname: Higashi
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Ozaki