中文摘要：

通过原位高压紫外-可见吸收光谱研究了2种溶剂（水溶液和体积比为4：1的甲醇-乙醇混合溶液）中亚甲基蓝（MB）分子聚集平衡状态的变化．采用金刚石对顶砧原位高压实验装置，在不同压力下测量亚甲基蓝溶液的吸收光谱，最高实验压力分别达到0．8GPa（水溶液）和8．7GPa（甲醇-乙醇溶液）．结果表明，随着压力的上升，亚甲基蓝溶液中单体分子和二聚体的吸收峰强度比不断下降，说明高压可以促进二聚体的形成，使亚甲基蓝溶液中分子的单体．二聚体动态平衡过程向二聚体方向移动．卸压后，亚甲基蓝溶液吸收光谱的强度降低，但吸收峰的强度比及峰位恢复到加压前的状态，表明高压下分子聚集平衡状态的变化是可逆的．

英文摘要：

The monomer-dimer equilibrium of methylene blue（MB） in two different solvents[ deionized water and 4 ： 1 （ volume ratio） methanol-ethanol ] was studied by in situ high pressure UV-Vis absorption spectroscopy. Using diamond anvil cell, the highest pressure conducted in the experiments was about 0.8 GPa in water and 8.7 GPa in methanol-ethanol solvent. The absorbance ratio of monomer to dimer decreased with the increase of pressure, indicating that high pressure can promote dimerization of MB. On release of pressure, the intensity of the peak did not return to original state, but the absorbance ratio of monomer to dimer returned to the initial value, showing that the changes of the absorption spectra under high pressure are reversible.