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.

Nonlinear order separation in two-dimensional electronic spectroscopy quantifies properties of higher-excited states

This paper demonstrates a technique to separate multiple nonlinear orders in two-dimensional electronic spectroscopy by varying pump pulse intensities, enabling the quantitative characterization of highly excited states, such as transition dipole moments and energy levels, in a squaraine dimer with excellent agreement between theory and experiment.

Katja Mayershofer, Peter A. Rose, Julian Lüttig, Luisa Brenneis, Simon Büttner, Jacob J. Krich, Tobias Brixner2026-05-25🔬 physics.optics

Frontier Orbital Engineering in Heteroatom-Doped Prototypical Organic Dyes for Dye-Sensitized Solar Cells

This study establishes an efficient, tuned DFT-TDDFT framework to screen heteroatom-doped organic dyes for dye-sensitized solar cells, revealing that electron-deficient boron doping effectively narrows the HOMO-LUMO gap and red-shifts charge-transfer excitations to enhance solar light harvesting.

Aditi Singh, Ram Dhari Pandey, Subrata Jana, Prasanjit Samal, Paweł Tecmer, Szymon Śmiga2026-05-22🔬 physics

Large Language Model Agent for User-friendly Chemical Process Simulations

This paper presents a Large Language Model agent integrated with AVEVA Process Simulation via the Model Context Protocol, which enables natural language interaction for automating complex chemical process tasks like analysis, optimization, and flowsheet synthesis, thereby enhancing both educational accessibility and professional efficiency while still requiring expert oversight.

Jingkang Liang, Niklas Groll, Gürkan Sin2026-05-22🤖 cs.AI

Accurate starting points for one-shot G0W0G_0W_0 and Bethe-Salpeter Equation calculations via effective tuning of range-separated hybrid functionals

This paper demonstrates that a recently proposed effective tuning protocol for range-separated hybrid functionals provides a computationally efficient and accurate alternative to conventional multi-step optimizations, yielding reliable starting points for one-shot G0W0G_0W_0 and Bethe-Salpeter Equation calculations of ionization potentials and excitation properties across diverse molecular systems.

Aditi Singh, Subrata Jana, Szymon Śmiga2026-05-22🔬 physics

Benchmarking machine-learned interatomic potentials for molecular infrared spectroscopy

This study benchmarks five machine-learned interatomic potentials (SchNet, FieldSchNet, SO3Net, PaiNN, and MACE) for predicting molecular infrared spectra, finding that while all models achieve high accuracy on training data, the equivariant architectures (SO3Net, PaiNN, and MACE) demonstrate superior generalization to unseen systems, with PaiNN offering the best balance of efficiency and accuracy and MACE providing the highest spectral accuracy.

Nitik Bhatia, Ondrej Krejci, Patrick Rinke2026-05-22🔬 physics

Dynamic electron correlation energy for multireference wavefunction methods from one- and two-electron reduced density matrices

This perspective reviews and benchmarks methods that recover dynamic correlation for multireference wavefunctions using low-order reduced density matrices, finding that while MC-srPDFT is the most accurate DFT-based approach, linearized AC0 outperforms DFT methods and rivals expensive perturbation theory in predicting spin-state energetics for transition-metal complexes.

Michał Hapka, Aleksandra Tucholska, Katarzyna Pernal2026-05-22🔬 physics

On the Regularity and Interpolation of Coupled Cluster Amplitudes in Canonical Orbital Basis

This paper theoretically establishes the real analyticity of single-reference coupled cluster amplitudes with respect to nuclear coordinates under non-degeneracy assumptions, identifies and mitigates regularity artifacts caused by canonical orbitals, and validates the feasibility of interpolating these amplitudes to reduce computational costs in molecular energy calculations.

Jonas Beck, Benjamin Stamm2026-05-22🔬 physics

Machine Learning Interatomic Potentials: Advancing Open-Source Software for Efficient and Scalable Molecular Simulation

This paper introduces mlip v2, a new generation of open-source software that enhances the efficiency, scalability, and flexibility of machine learning interatomic potentials through a redesigned modular API, a high-performance equivariant backend, and advanced capabilities like the eSEN architecture and improved electrostatics handling.

Christoph Brunken, Titouan Cormier, Lucien Walewski, Marco Carobene, Yessine Khanfir, Zachary Weller-Davies, Miguel Bragança, Armand Picard, Adrien Pichard, Leon Wehrhan, Heloise Chomet, Eszter Varga- (…)2026-05-22🔬 physics

PASPT2: a size-extensive and size-consistent partial-active-space multi-state multi-reference second-order perturbation theory for strongly correlated electrons

This paper introduces PASPT2, a novel partial-active-space multi-state multi-reference second-order perturbation theory that achieves strict size-extensivity and size-consistency for strongly correlated systems by employing a specialized reference-specific zeroth-order Hamiltonian to eliminate disconnected terms found in its parent coupled-cluster formulation.

Chunzhang Liu, Ning Zhang, Wenjian Liu2026-05-21🔬 physics

DynaMate2: Democratization of Agentic AI for Expert-Designed Custom Workflows

DynaMate2 is an open-source, hierarchical agentic framework that democratizes AI-driven scientific workflows by allowing researchers to easily convert their existing expert-defined Python tools into AI-callable components without requiring the LLM to generate scientific code, thereby lowering the barrier to automation in domains like computational chemistry.

Orlando A. Mendible-Barreto, Ajay Vallabh, Ubaldo M. Córdova-Figueroa, Yamil J. Colón2026-05-21🔬 physics