摘要：

利用混合量子-经典动力学模拟方法, 考察了不同管径的单壁碳纳米管(SWCT)中受限溶剂氩的径向分布以及溶质I2分子的振动弛豫动力学, 给出了I2分子的振动频率位移、振动弛豫时间随受限碳纳米管管径尺寸变化的关系. 以I2分子的振动频率位移为探针, 根据I2分子与周围环境作用的实时信息, 分析了管壁、受限溶剂对光谱探针的贡献, 在原子、分子层次上揭示了诱导频率位移的微观机制; 此外, 通过分析探针光谱的敏感性以及探针分子频率位移与振动弛豫时间的关系, 进一步阐明了振动频率位移是考察受限凝聚相中分子间相互作用的较好的探针.

关键词: 振动光谱探针, 混合量子-经典动力学, 单壁碳纳米管, 振动弛豫时间, 振动频率位移

Abstract:

The radial distributions of argon as a solvent as well as the vibrational relaxation dynamics of the solute I2 confined in a single-walled carbon nanotube (SWCT) were investigated by mixed quantum-classical molecular dynamics simulations. Functions of the vibrational frequency shift and the vibrational relaxation time of I2 with varying radii were presented. Using the frequency shift of I2 as a spectral probe, an analysis of the instantaneous interactions of I2 with the surroundings was determined by breaking down the shift into the contributions of the nanotube and the solvent atoms. Detailed mechanistic information related to the shift was investigated at the atomic and molecular level. In addition, by analysis of the sensitivity of the spectral probe and the dependence of the frequency shift on the vibrational relaxation time of the probe molecule, we conclude that the frequency shift is a good spectral probe to investigate the interactions in confined condensed phases.

Key words: Vibrational spectral probe, Mixed quantum-classical molecular dynamics, Single-walled carbon nanotube, Vibrational relaxation time, Vibrational frequency shift