1997 Fiscal Year Final Research Report Summary
On the dynamics and phase properties of water molecules spread over 2D space
| Project/Area Number |
08454227
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
機能・物性・材料
|
|---|
| Research Institution | Okayama University of Science |
|---|
Principal Investigator |
KITTAKA Shigeharu Okayama Univ.Sci., Fac.Sci., Professor, 理学部, 教授 (60068905)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KURODA Yasushige Okayama Univ., Fac.Sci., Ass.Professor, 理学部, 助教授 (40116455)
TAKAHARA Shuichi Okayama Univ.Sci., Fac.Sci., Res.Ass., 理学部, 助手 (20289135)
TAKENAKA Tohru Okayama Univ.Sci., Fac.Sci., Professor, 理学部, 教授 (00027020)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Keywords | physisorbed water / interlayr water / two-dimensional phase / chromium oxide / vanadium oxide hydrate / monolayr water / quasi-elastic neutron scattering / dynamics |
|---|
| Research Abstract |
Dynamic properties of water molecules spread in a two-dimensional field were studied by applying the quasi-elastic neutron scattering spectroscopy, dielectric measurements, and NMR measurements.
(1) On a hydroxylated chromium oxide surface water molecules are adsorbed by forming the homogeneous two-dimensional phase, in which lattice gas-condensed phase (liquid or solid) equilibrium is observed. Main purpose of the present study is to assign the condensed phase above and below the 2D-critical temperature (30ﾟC). According to the quasi-elastic neutron scattering there found rotational motion of water molecules below the 2D critical temperature but no translational diffusion. Dielectric measurements supported this with the fact that some kind of dielectric relaxation occurs in the same temperature range. Quasi-elastic neutron scattering measurements above 2D critical temperature (47.6ﾟC) gave translational diffusion coefficient 3.1*10^<-10> m^2s^<-1>. These facts indicate that adsorbed ph
… More
ase below the 2D critical temperature is a solid water. Alcohol adsorption was done comparatively with the H_2O adsorption, in which two-dimensional condensation was not observed in a monolayr but special association was found in double layr range. Monte Carlo simulations for the adsorption of water and methanol using the program Cerius2 gave the structure different from the one presumed from the IR measurements.
(2) Dynamic properties of interlayr water molecules in the layred vanadium pentoxide hydrate were studied by quasi-elastic neutron scattering, NMR,and FT-IR.C_<2v> rotation axis of monolayr water molecule leans from c-axis by 18ﾟ. Neutron scattering measurements substantiate that water molecules diffuse in a two dimensionally confined space and give the self-diffusion coefficient 7.2m^2s^<-1> for double layr water. This supports the idea proposed by Dianoux et al for the self-diffusion process in a confined space. Analysis of the diffusion observed by adsorption rate measurements suggested that the diffusion path of the particle ranges a few mm. Ammonia was intercalated between the layrs in two modes, molecular and ionized (ammonium) forms. Less
|
