title: Bifurcate localization modes of excess electron in aqueous Ca(2+)amide solution revealed by ab initio molecular dynamics simulation: towards hydrated electron versus hydrated amide anion.
abstract: In this work, we conduct ab initio molecular dynamics simulations on the localization dynamics of an excess electron (EE) in acetamide/Ca(2+) aqueous solutions with three different interaction modes of Ca(2+) with acetamide: tight contact, solvent-shared state, and separated interaction. The simulated results reveal that an EE could exhibit two different localization behaviors in these acetamide/Ca(2+) aqueous solutions depending on different amideCa(2+) interactions featuring different contact distances. For the tight contact and solvent-shared state of amideCa(2+) solutions, vertically injected diffuse EEs follow different mechanisms with different dynamics, forming a cavity-shaped hydrated electron or a hydrated amide anion, respectively. Meanwhile, for the separated state, only one localization pattern of a vertically injected diffuse EE towards the formation of hydrated amide anion is observed. The hindrance of hydrated Ca(2+) and the attraction of the hydrated amide group originating from its polarity and low energy π* orbital are the main driving forces. Additionally, different EE localization modes have different effects on the interaction between the amide group and Ca(2+) in turn. This work provides an important basis for further understanding the mechanisms and dynamics of localizations/transfers of radiation-produced EEs and associated EE-induced lesions and damage to biological species in real biological environments or other aqueous solutions.
authors.affiliation: Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, 250100, P. R. China. byx@sdu.edu.cn.
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Bu
mesh_terms: D000577:Amides / Q000737:chemistry*; D000838:Anions / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D004583:Electrons; D056004:Molecular Dynamics Simulation / Q000592:standards*; D014867:Water / Q000737:chemistry*
chemical_list: D000577:Amides; D000838:Anions; D014867:Water; D002118:Calcium