The phenomena of solvent exchange control the process of solvating ions, protons, and charged molecules. Building upon our extension of Marcus’ philosophy of electron transfer, we provide a new perspective of ultrafast solvent exchange mechanism around ions measurable by two-dimensional infrared (2DIR) spectroscopy. In this theory, solvent rearrangement drives an ion-bound water to an activated state of higher coordination number, triggering ion-water separation that leads to the solvent-bound state of the water molecule. This ion-bound to solvent-bound transition rate for a ${\text{BF}}_4^{-}$-water system is computed using ab initio molecular dynamics and Marcus theory, and is found to be in excellent agreement with the 2DIR measurement.

溶剂交换现象控制着离子，质子和带电分子的溶剂化过程。在扩展了马库斯（Marcus）电子转移哲学的基础上，我们提供了围绕离子的超快速溶剂交换机制的新观点，该离子可通过二维红外（2DIR）光谱测量。在此理论中，溶剂重排将离子结合的水驱动到更高配位数的活化状态，从而触发离子水分离，从而导致水分子与溶剂结合的状态。该离子结合到溶剂结合的转变速率为${\text{高炉}}_4^{--}$-水系统是使用从头算分子动力学和Marcus理论计算得出的，并且与2DIR测量非常吻合。