期刊
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
卷 19, 期 32, 页码 21540-21547出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c7cp02065a
关键词
-
资金
- National Natural Science Foundation of China [11364027]
- Inner Mongolia University of Science and Technology Innovation Fund [2015QDL14]
The OH/OD stretch band on Raman spectra of water is complex, and understanding the spectral features based on water structure needs further study. This study investigates Raman spectra of isotopic substitution (IS) of water (with volume ratio VH2O/VD2O of 0/1, 1/4, 1/1, 4/1 and 1/0) at temperatures from 303 to 573 K. The data show that the OH and OD stretch band profiles are similar in their dependences on temperature and IS ratio. IS reduces the band widths at low temperatures but the reducing effect diminishes above B450 K, due to the largely enhanced intensity of the high-frequency shoulder (B3650 cm(-1)/2690 cm(-1)), which turns into the main peak for the OH (or OD) stretch bands when VH2O/VD2O (or VD2O/VH2O) reaches 1/4 at temperatures over B510 K. These spectral features strongly indicate a multi-structure model stating that water has various local hydrogen bonding (HB) environments. Intermolecular vibrational couplings are important in determining the band width, while intramolecular vibrational couplings are not recommended for interpreting the OH/OD stretch band. Five dominant HB configurations are identified in water: two types of tetrahedral, single donor (SD) HB configuration, single hydrogen-bonded water (SHW), and free water (FW) without any hydrogen bonds, which are represented by five sub-bands. It is estimated that most (450%) of the water molecules are in highly asymmetric HB environments (SD and SHW). The increase of temperature breaks HB structure and IS further promotes structure transition from tetrahedral to SD, SHW and FW. Then, number of hydrogen bonds in water are greatly reduced by temperature and IS.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据