Two co-existing and opposing mechanisms of proton transfer in one-dimensional open-end water chains

Xinrui Yang; Famin Yu; Lu Wang; Rui Liu; Yue Xin; Rui Li; Yulei Shi; Zhigang Wang

doi:10.1063/5.0204275

Two co-existing and opposing mechanisms of proton transfer in one-dimensional open-end water chains

J Chem Phys. 2024 May 21;160(19):194904. doi: 10.1063/5.0204275.

Authors

Xinrui Yang¹, Famin Yu¹, Lu Wang¹, Rui Liu², Yue Xin¹, Rui Li^{2

3}, Yulei Shi³, Zhigang Wang^{1

2

4}

Affiliations

¹ Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China.
² Key Laboratory of Material Simulation Methods and Software of Ministry of Education, College of Physics, Jilin University, Changchun 130012, China.
³ Department of Physics, Capital Normal University, Beijing 100048, China.
⁴ Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China.

PMID: 38752536
DOI: 10.1063/5.0204275

Abstract

The proton transport in one-dimensional (1D) confined water chains has been extensively studied as a model for ion channels in cell membrane and fuel cell. However, the mechanistic understanding of the proton transfer (PT) process in 1D water chains remains incomplete. In this study, we demonstrate that the two limiting structures of the hydrated excess proton, H5O2+ (Zundel) and H3O+ (linear H7O3+), undergo a change in dominance as the water chain grows, causing two co-existing and opposing PT mechanisms. Specifically, H5O2+ is stable in the middle of the chain, whereas H3O+ serves as a transition state (TS). Except for this region, H3O+ is stabilized while H5O2+ serves as a TS. The interaction analysis shows that the electrostatic interaction plays a crucial role in the difference in PT mechanisms. Our work fills a knowledge gap between the various PT mechanisms reported in bulk water and long 1D water chains, contributing to a deeper understanding of biological ion channels at the atomic level.