Structures and spectroscopic properties of K+(H2O)n with n = 1–10 clusters based on density functional theory

Abstract

Hydrated potassium ion clusters widely exist in salt solutions and biological cells. To explore the configuration of hydrated potassium ions, a global search for the structures from 4 to 10 hydrated potassium ion clusters is performed using the genetic algorithm with density functional theory, followed by high-level ab initio optimization and energetic calculation. Potassium ion remains on the surface of the clusters rather than surrounded by water molecules as the cluster size increases. The simulated infrared (IR) spectra with anharmonic correction of clusters could efficiently reproduce the experimental results. The interaction between the K+ cation and the water molecules resulted in little deviation (<300 cm−1) of the adjacent O–H stretching mode.