English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The potential energy landscape (PEL) formalism is a tool within statisticalmechanics that has been used in the past to calculate the equation of states(EOS) of classical rigid model liquids at low temperatures, where computersimulations may be challenging. In this work, we use classical moleculardynamics (MD) simulations and the PEL formalism to calculate the EOS of theflexible q-TIP4P/F water model. This model exhibits a liquid-liquid criticalpoint (LLCP) in the supercooled regime, at ($P_c = 150$ MPa, $T_c = 190$ K,$\rho_c = 1.04$ g/cm$^3$) [using the reaction field technique]. The PEL-EOS ofq-TIP4P/F water, and the corresponding location of the LLCP, are in very goodagreement with the MD simulations. We show that the PEL of q-TIP4P/F water isGaussian which allows us to calculate the configurational entropy of thesystem, $S_{conf}$. The $S_{conf}$ of q-TIP4P/F water is surprisingly similarto that reported previously for rigid water models, suggesting thatintramolecular flexibility does not necessarily add roughness to the PEL. Wealso show that the Adam-Gibbs relation, which relates the diffusion coefficient$D$ with $S_{conf}$, holds for the flexible q-TIP4P/F water model. Overall, ourresults indicate that the PEL formalism can be used to study molecular systemsthat include molecular flexibility, the common case in standard force fields.This is not trivial since the introduction of large bending/stretching modefrequencies is problematic in classical statistical mechanics. For example, asshown previously, we find that such high-frequencies lead to an unphysical(negative) entropy for q-TIP4P/F water (yet the PEL formalism can be appliedsuccessfully).

Potential Energy Landscape of a Flexible Water Model: Equation-of-State, Configurational Entropy, and Adam-Gibbs Relationship