混合量子-经典动力学方法研究反胶团水池中Ⅰ_2分子的振动频率位移

Mixed Quantum-Classical Dynamics Method Study of the Vibrational Frequency Shift of Ⅰ_2 in the Water Pool of Reverse Micelles

结合Monte Carlo模拟技术,提出了一种反胶团溶液的快速数学建模新方法.利用量子-经典动力学模拟方法,考察了I2分子受限于两个不同尺寸的反胶团水池中振动频率的诱导位移及谱分布.结果表明,相比于体相水,受限于反胶团水池中I2分子的诱导位移表现为蓝移,且蓝移大小随水池尺寸变化不大.通过对I2分子与周围环境相互作用的分解分析,得到了水池水、表面活性剂以及有机溶剂分子对I2分子振动频率诱导位移的瞬态贡献,揭示了I2分子振动弛豫的微观作用机制.此外,对于受限水池中水分子的诱导贡献及空间分布的研究表明,I2分子振动频率位移的诱导贡献主要来自于第一溶剂层,它是由4个水分子蓝移贡献和2个水分子红移贡献组成.

A new approach to rapidly obtain a stable topological structure of a reverse micelle was investigated using a mathematical method combined with a Monte Carlo simulation. The vibrational frequency shift and the spectral distribution of I2, which was confined in a water pool of two different sizes in reverse miceUes （RMs）, were calculated by mixed quantum-classical molecular dynamics simulations. Results indicate that the vibrational frequency is blue-shifted for both RMs studied compared to the vibrational frequency for I2 in bulk water. This difference is not obviously related to RM size. By analysis of the interactions of I2 with its surroundings, the instantaneous frequency shift of I2 may consist of contributions from the water pool, the surfactant, and the organic solvent while the data provide detailed mechanistic information. The induced contribution and spatial distribution of water molecules confined in the water pool suggest that the induced frequency shift of I2 mainly originates from the first solvation layer, which is composed of contributions from 4 blue-shifted and 2 red-shifted water molecules.