This collection explores the fascinating intersection where the laws of physics meet the complex machinery of chemistry. Here, researchers investigate how quantum mechanics governs molecular bonds, how light interacts with matter at the atomic scale, and how fundamental forces shape chemical reactions. It is a realm where abstract mathematical models collide with tangible substances to reveal the hidden mechanisms driving our material world.

On Gist.Science, we process every new preprint in this category directly from arXiv to make these discoveries accessible to everyone. Whether you are a seasoned expert or a curious reader, you will find both plain-language explanations and detailed technical summaries for each paper. Below are the latest contributions from the community pushing the boundaries of physical chemistry.

Controlling S^2\langle \hat{S}^2 \rangle in Broken-symmetry Density Functional Theory Calculations via Constrained Optimization

This paper introduces a constrained optimization method using Lagrange multipliers to enforce a target spin-squared expectation value in broken-symmetry DFT calculations, thereby mitigating spin contamination and yielding more consistent and accurate magnetic exchange coupling constants across various systems and functionals.

Jeronimo Lira, Juan E. Peralta2026-06-03🔬 physics

Ab Initio Free Energy Surfaces for Coupled Ion-Electron Transfer

This paper presents a first-principles framework that extends Marcus theory to construct two-dimensional free energy surfaces for coupled ion-electron transfer (CIET) by conditioning diabatic nuclear configurations on interfacial anisotropy, revealing that CO2 reduction kinetics on gold electrodes are governed by saddle-point barriers that differ significantly from traditional one-dimensional treatments.

Ethan Abraham, Martin Z. Bazant, Troy Van Voorhis2026-06-02🔬 cond-mat.mtrl-sci

Analytical Excited-State Gradients and Derivative Couplings in TDDFT with Minimal Auxiliary Basis Set Approximation and GPU Acceleration

This paper presents the first implementation of analytical excited-state gradients and derivative couplings within the TDDFT-ris framework, demonstrating that this GPU-accelerated approach with a minimal auxiliary basis set achieves a two- to three-fold speedup over standard TDDFT while maintaining sufficient accuracy for geometry optimizations and emission calculations, despite minor errors in derivative couplings between nearly degenerate states.

Zhichen Pu, Xiaojie Wu, Yuanheng Wang, Cheng Fan, Wen Yan, Zehao Zhou, Yi Qin Gao, Qiming Sun2026-06-02🔬 physics

Impact of the sodium and calcium chlorides uptake on the interfacial behavior of ice: premelting, structure, and dynamics

Through computer simulations and thermodynamic analysis, this study demonstrates that undersaturated sodium and calcium chloride surface layers on ice form genuine quasi-brine states distinct from bulk three-phase coexistence, which significantly increase premelting thickness while retaining structural and dynamical properties similar to bulk electrolyte solutions.

Łukasz Baran, Luis G. MacDowell2026-06-02🔬 cond-mat

Reassessing carotenoid photophysics: shedding light on dark states

Using femtosecond stimulated resonance Raman spectroscopy, this study resolves vibrational signatures of three previously elusive dark electronic states in carotenoids, thereby addressing long-standing controversies and providing a refined spectroscopic framework for understanding their roles in photosynthesis.

Roxanne Bercy, Viola Dmello, Andrew Gall, Cristian Ilioaia, Andrew A. Pascal, Juan Jose Romero, Bruno Robert, Manuel J. Llansola-Portoles2026-06-02🔬 physics

From Evaluation to Design: Using Potential Energy Surface Smoothness Metrics to Guide Machine Learning Interatomic Potential Architectures

This paper introduces the Bond Smoothness Characterization Test (BSCT), a computationally efficient metric that detects potential energy surface non-smoothness to both validate Machine Learning Interatomic Potentials and guide iterative architectural improvements, resulting in models that achieve low regression errors while ensuring stable molecular dynamics simulations.

Ryan Liu, Eric Qu, Tobias Kreiman, Samuel M. Blau, Aditi S. Krishnapriyan2026-06-02🔬 cond-mat.mtrl-sci