Reorientation of OH-group connecting bifurcated H-bond acceptors in liquid water.

Graphical abstract Highlights • The orientational TCF of the OH-group connecting bifurcated HB-acceptors has been studied. • Both simulations and the normal-mode approach were used in our studies. • The mean-square rotational displacement of the OH-group reorientation were calculated. • The deviation angle of the OH-group before entering the diffusive regime was estimated. Abstract The OH-group connecting bifurcated H-bond (HB) acceptors is one case of the three-centered HBs found in physical and biological systems. An example is the transition state of molecular reorientation jump mechanism in liquid water, ionic solutions, and hydration shells of biomolecules. In this Letter, the orientational time correlation functions of these special OH-groups in water were studied by performing molecular dynamics simulations and using the normal-mode approach developed recently. The reorientation angle of the OH-group before entering the diffusive regime can be estimated through the plateau in the mean-square rotational displacement calculated by several methods. [ABSTRACT FROM AUTHOR]