The quest for self-consistency in hydrogen-bond definitions

TL;DR

This study compares six common hydrogen-bond definitions across various water models and temperatures, revealing weak agreement and the need for specific cutoff adjustments, highlighting the challenge of universal hydrogen-bond criteria.

Contribution

It provides a comprehensive comparative analysis of hydrogen-bond definitions, emphasizing their inconsistencies and the necessity for tailored cutoff parameters in classical water models.

Findings

Weak agreement among definitions across conditions

Cutoff choices depend on temperature and water model

Discrepancies found in recent hydrogen-bond definitions

Abstract

In the last decades several hydrogen-bond definitions were proposed by classical computer simulations. Aiming at validating their self-consistency on a wide range of conditions, here we present a comparative study of six among the most common hydrogen-bond definitions for temperatures ranging from 220K to 400K and six classical water models. Our results show that, in the interval of temperatures investigated, a generally weak agreement among definitions is present. Moreover, cutoff choice for geometrically based definitions depends on both temperature and water model. As such, analysis of the same water model at different temperatures as well as different water models at the same temperature would require the development of specific cutoff values. Interestingly, large discrepancies were found between two hydrogen-bond definitions which were recently introduced to improve on more conventional methods. Our results anticipate that a more universal way to characterize hydrogen-bonds in classical molecular systems is needed.