摘要
水在纳米通道中会表现出与体相水不一样的独特结构和动力学性质,但现有实验技术依然无法有效地进行探测和表征.光谱是用于研究和鉴别物质成分及其特性的有效技术手段,因此本文利用分子动力学模拟计算了受限在(6,6)单壁碳纳米管中一维有序单链状水(single-file water,SW)的红外吸收光谱,研究发现SW在0—35 THz区域内的主峰相对于体相水有明显的蓝移和增强,分析表明是由于SW的有序性导致分子间的摆转(libration)振动(包括rock,twist,wag三种模式)耦合权重发生变化引起的,即频率较高的twist和wag模式在SW中相对体相水中束缚能减小,振动相对容易发生,从而导致谱峰发生蓝移和增强.与此同时,研究表明SW光谱分量特性能很好地预测和解释SW的结构和动力学性质.进一步地,太赫兹电场效应模拟实验验证了SW的红外吸收能力基本符合光谱的分布特性.
Compared with bulk water(BW),the water in nanochannels usually shows unique structural and dynamic properties,which is still unable to be effectively detected and characterized by existing experimental techniques.The spectrum is an effective technical means for studying and identifying the material composition and characteristics.In this study,the infrared absorption spectra of one-dimensional ordered single-file water(SW)confined in(6,6)single-walled carbon nanotubes are calculated by molecular dynamics simulation.It is found that the ordered arrangement of SW results in an obvious blue shift and enhancement of the spectral peak in the 0–35 THz range relative to the bulk water.The analysis shows that this phenomenon is caused by the change of coupling weight of libration vibrations(including rock,twist and wag modes)of SW.The twist vibration mode and wag vibration mode with higher frequency are relatively easy to occur because the binding energy decreases under the single chain structure of water,which results in the blue shift and enhancement of the spectral peak.Meanwhile,the present study shows that the spectral component characteristics of SW can well predict and explain the structural and dynamic properties of SW.Further,terahertz simulation experiments show that the infrared absorption capacity of SW basically conforms with the spectral distribution characteristics.
作者
章其林
王瑞丰
周同
王允杰
刘琪
Zhang Qi-Lin;Wang Rui-Feng;Zhou Tong;Wang Yun-Jie;Liu Qi(School of Mathematics-Physics and Finance,Anhui Polytechnic University,Wuhu 241000,China;School of Materials Science and Engineering,Anhui Polytechnic University,Wuhu 241000,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第8期176-184,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11604001)
安徽省教育厅高校杰出青年科研项目(批准号:2022AH020064)
安徽省自然科学基金(批准号:2008085ME132)资助的课题
中国科学技术大学超算中心的资助
关键词
单链水
红外吸收光谱
分子动力学
太赫兹电场
single-file water
infrared absorption spectrum
molecular dynamics
terahertz electric field
