title: Pore-size dependent THz absorption of nano-confined water.
abstract: We performed a THz absorption spectroscopy study on liquid water confined in mesoporous silica materials, MCM-41-S-18 and MCM-41-S-21, of two different pore sizes at room temperatures. We found that stronger confinement with a smaller pore size causes reduced THz absorption, indicating reduced water mobility due to confinement. Combined with recent theoretical studies showing that the microscopic structure of water inside the nanopores can be separated into a core water region and an interfacial water region, our spectroscopy analysis further reveals a bulk-water-like THz absorption behavior in the core water region and a solid-like THz absorption behavior in the interfacial water region.
authors.forename: Chi-Kuang
authors.initials: CK
authors.lastname: Sun
authors.forename: Borwen
authors.initials: B
authors.lastname: You
authors.forename: Yu-Ru
authors.initials: YR
authors.lastname: Huang
authors.forename: Kao-Hsiang
authors.initials: KH
authors.lastname: Liu
authors.forename: Shusaku
authors.initials: S
authors.lastname: Sato
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Irisawa
authors.forename: Motoki
authors.initials: M
authors.lastname: Imamura
authors.forename: Chung-Yuan
authors.initials: CY
authors.lastname: Mou
mesh_terms: D065966:Absorption, Physicochemical; D008958:Models, Molecular; D008968:Molecular Conformation; D058608:Nanopores; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D055068:Terahertz Spectroscopy; D014867:Water / Q000737:chemistry*
chemical_list: C509968:MCM-41; D014867:Water; D012822:Silicon Dioxide