International Journal of Quantum Chemistry最新文献

{"title":"First-Principles Insights into Asymmetric Surface Reactivity of Janus WSTe Monolayers","authors":"Jinying Li,&nbsp;Yifan Wang,&nbsp;He Liu,&nbsp;Chunwei Yang","doi":"10.1002/qua.70274","DOIUrl":"https://doi.org/10.1002/qua.70274","url":null,"abstract":"<div>\u0000 \u0000 <p>The intrinsic asymmetric surface reactivity of Janus WSTe monolayers is investigated using first-principles calculations. The broken inversion symmetry generates a macroscopic polarization that manifests as an effective built-in electric field of approximately 0.08 V/Å, driving spatial separation of frontier molecular orbitals and anisotropic orbital hybridization. The Te-terminated surface exhibits a higher electrophilic Fukui function of 0.18 e/ų, while the S-terminated surface shows a higher nucleophilic Fukui function of 0.15 e/ų. ELF analysis reveals diffuse delocalized electron basins at the Te-terminated surface and compact localized basins at the S-terminated surface. Hydrogen chemisorbs strongly at the S-terminated surface with an adsorption energy of −2.33 eV, whereas carbon monoxide exhibits only weak physisorption. The preferential H adsorption at the S-terminated surface correlates with its higher nucleophilic Fukui function, though the detailed orbital matching mechanism involves both the electron-accepting character of the S site and the radical reactivity of the H atom. These results establish a quantum mechanical correlation among structural asymmetry, electronic structure, and surface chemical reactivity.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fault-Tolerant Quantum Simulation of the Pauli-Breit Hamiltonian for Ab Initio Hybrid Quantum-Classical Molecular Design With Applications to Photodynamic Therapy","authors":"Emil Zak","doi":"10.1002/qua.70269","DOIUrl":"https://doi.org/10.1002/qua.70269","url":null,"abstract":"<div>\u0000 \u0000 <p>Relativistic spin effects are driving subtle molecular processes ranging from intersystem crossing in photodynamic therapy to spin-mediated catalysis and high-resolution spectroscopy. These effects can be described by the Pauli-Breit Hamiltonian, which extends the nonrelativistic electronic Hamiltonian by including explicit one- and two-electron spin-orbit and spin-spin interactions. However, first-principles simulations of the full Pauli-Breit Hamiltonian quickly become intractable on classical computers due to the rapid growth of Hilbert space dimension and the complexity of two-body spin-dependent terms. In this work, we propose a fault-tolerant quantum algorithm for computing molecular energy levels and properties governed by the Pauli-Breit Hamiltonian. The central result of the paper is an explicit block-encoding construction for the relativistic Hamiltonian in a second-quantized, doubly factorized representation. By reformulating the Pauli-Breit Hamiltonian in a symmetry-adapted Majorana basis, we construct efficient linear-combination-of-unitaries circuits that encode both one- and two-electron spin-orbit coupling without resorting to effective or mean-field approximations. We introduce spin-controlled Pauli-SWAP networks that decouple spin and orbital control logic, enabling a unified treatment of relativistic spin mixing with only a modest overhead relative to spin-free electronic structure simulations. We analyze the resulting quantum resources in terms of logical qubit counts and T-gate complexity, and show that the inclusion of spin degrees of freedom does not fundamentally worsen the asymptotic scaling. The prefactor in our approach is 2–4 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation>$$ times $$</annotation>\u0000 </semantics></math> lower than if the linear-combination of unitaries technique was applied directly. The present manuscript focuses on explicit circuit constructions and scaling analysis, rather than molecule-specific numerical resource estimates. To illustrate one prospective application, we outline a first-principles hybrid quantum-classical workflow for the rational design of photodynamic therapy photosensitizers, artificial photosynthesis catalysts, and other molecular systems where accurate treatment of relativistic spin effects is essential.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metal–Organic Framework [Ag24(trz)18]6+ as a Nanocarrier Agent for Ibuprofen Drug: A DFT Study","authors":"Juliana Cirino dos Santos,&nbsp;Osmair Vital de Oliveira,&nbsp;Antônio Francisco Cruz Arapiraca,&nbsp;José Divino dos Santos","doi":"10.1002/qua.70285","DOIUrl":"https://doi.org/10.1002/qua.70285","url":null,"abstract":"<div>\u0000 \u0000 <p>This study employed density functional theory to investigate the metal–organic framework [Ag₂₄(trz)₁₈]⁶⁺ as a potential nanocarrier for ibuprofen (IBF), a nonsteroidal anti-inflammatory drug. Encapsulation occurs through a physical process characterized by a favorable interaction energy of −62.37 kcal/mol, while preserving the structure of [Ag₂₄(trz)₁₈]⁶⁺. Reactivity parameters indicate that both the isolated [Ag₂₄(trz)₁₈]⁶⁺ and the IBF@[Ag₂₄(trz)₁₈]⁶⁺ complex are chemically and kinetically stable. The LUMO energy suggests that [Ag₂₄(trz)₁₈]⁶⁺ prevents IBF from accepting electrons during chemical reactions. The IBF encapsulated within [Ag₂₄(trz)₁₈]⁶⁺ transfers part of its charge to the nanocage, maintaining its cavity partially in a neutral state. Additionally, quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses indicate that the encapsulation is a physical process driven by van der Waals forces. Overall, our study suggests that the [Ag₂₄(trz)₁₈]⁶⁺ nanocage is a promising candidate for use as a nanocarrier for IBF.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adsorption and Co-Adsorption of CO and H2O on Ce2O4 and CeMO4 (M = Ti and Sn) Nanoclusters: A DFT-Based Perspective","authors":"Partha Pratim Churi,&nbsp;Gaurisankar Phukan,&nbsp;Shilpa Neog,&nbsp;Priyanka Dutta,&nbsp;Nand Kishor Gour,&nbsp;Ramesh Chandra Deka","doi":"10.1002/qua.70282","DOIUrl":"https://doi.org/10.1002/qua.70282","url":null,"abstract":"<div>\u0000 \u0000 <p>The B3LYP-D3/def2-TZVPP level of theoretical study is performed to examine the stability of pure Ce₂O₄ and CeMO₄ (M = Ti and Sn) clusters. Adsorption and Co-adsorption of CO and H₂O are also carried out on pure and doped clusters. Additionally, global and local reactivity descriptors, as well as natural bonding orbital (NBO) analysis, are employed to gain insights into the adsorption characteristics of CO and H₂O molecules on all the clusters. To understand how bond lengths of clusters and adsorbates change with the quality of charge transfer, we utilize stabilization energy (<i>E</i>⁽²⁾) calculations in our charge transfer analysis. This approach would be considered as a foundational step for future research into the water-gas shift reaction (WGSR).</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symbolic Valence Bond Theory for Chemists: The symvb Package","authors":"Punhasa S. Senanayake,&nbsp;Marat R. Talipov","doi":"10.1002/qua.70284","DOIUrl":"https://doi.org/10.1002/qua.70284","url":null,"abstract":"<div>\u0000 \u0000 <p>Valence-bond (VB) theory provides a structural language for reasoning about molecular electronic structure, but its practical use is limited by the algebra of matrix elements between non-orthogonal VB structures. We introduce symvb, a SymPy-based package that automates this algebra through Löwdin's cofactor expansion and returns symbolic VB Hamiltonian and overlap matrices, closed-form energies, and Chirgwin–Coulson weights as functions of the atomic-orbital integrals. In <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>H</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {mathrm{H}}_2 $$</annotation>\u0000 </semantics></math>, decreasing overlap shifts the bonding stabilization toward covalent–ionic resonance, which is the hallmark of charge-shift bonding. In the allyl anion, the long-bond Rumer weight, a biradical signature, grows from 1/8 to 1/2 with on-site repulsion. In the mixed-valence disphenoid <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mfenced>\u0000 <msub>\u0000 <mi>H</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mfenced>\u0000 <mn>2</mn>\u0000 <mrow>\u0000 <mo>•</mo>\u0000 <mo>+</mo>\u0000 </mrow>\u0000 </msubsup>\u0000 </mrow>\u0000 <annotation>$$ {left({mathrm{H}}_2right)}_2^{bullet +} $$</annotation>\u0000 </semantics></math>, correlation shifts the Robin–Day boundary toward weaker coupling. In benzene, a covalent-only model gives the wrong sign for the energy response to weakening a single bond, exposing the essential role of ionic structures. Thus, symvb provides a reusable symbolic workflow for constructing and interpreting non-orthogonal VB models.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the Excited State Proton Transfer Mechanism of Salicylamide: A TD-DFT Study","authors":"Xiaohao Jiang,&nbsp;Yinhua Ma,&nbsp;Xuesong Xu,&nbsp;Hongming Yin","doi":"10.1002/qua.70210","DOIUrl":"https://doi.org/10.1002/qua.70210","url":null,"abstract":"<div>\u0000 \u0000 <p>Excited-state proton transfer (ESPT) plays a crucial role in photochemical processes, serving as an important mechanism for modulating molecular structures and fluorescence behaviors. In this study, the ESPT mechanism of salicylamide (SAM) was systematically investigated in the gas phase, aqueous solution, and ethanol solution using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. Explicit solvent-complex models were constructed to evaluate solvent effects. The calculated results indicate that ESPT is both thermodynamically and kinetically feasible for SAM in the gas phase. In contrast, in aqueous and ethanol environments, ESPT occurs through intermolecular proton transfer facilitated by solvent molecules, giving rise to dual fluorescence behavior. The primary fluorescence emission originates from the local excitation.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CO2 and C3O6 Coordination to Ni2+, Cu2+, and Zn2+: Metal-Dependent Multiligand Binding and Counterion Effects","authors":"Puthiyavalappil K. Arathi,&nbsp;Mini Bharati Ahirwar,&nbsp;Cherumuttathu H. Suresh","doi":"10.1002/qua.70279","DOIUrl":"https://doi.org/10.1002/qua.70279","url":null,"abstract":"<div>\u0000 \u0000 <p>A density functional theory study of CO₂ and the cyclic trimer 1,3,5-trioxanetrione (C₃O₆) coordination to Ni²⁺, Cu²⁺, and Zn²⁺ is presented to elucidate how metal identity, ligand topology, and coordination environment govern multiligand binding thermodynamics. In the absence of coordinating anions, both CO₂ and C₃O₆ follow an intrinsic affinity order of Ni²⁺ &gt; Cu²⁺ &gt; Zn²⁺. Successive ligand addition leads to cumulative stabilization for all metals, while decreasing per-ligand interaction and free energies indicate progressive electronic saturation and coordination-sphere crowding. Coordination of C₃O₆ induces localized structural activation, reflected in characteristic C–O bond distortions that follow the same metal-dependent trend. The ligand environment significantly modulates binding: weakly coordinating BF₄⁻ counterions reduce interaction strengths and alter relative affinities, whereas coordinating Cl⁻ ligands occupy metal coordination sites and limit ligand accessibility. Despite these effects, Ni²⁺ retains favorable binding across coordination numbers, while Cu²⁺ and Zn²⁺ show more limited coordination. Comparison with equivalent monomeric CO₂ assemblies reveals that the C₃O₆ binding mode provides enhanced metal–ligand stabilization per CO₂ equivalent, arising from its cyclic, multidentate nature. Although this stabilization partially compensates the intrinsic endothermicity associated with C₃O₆ formation, the process remains thermodynamically uphill with respect to CO₂. Overall, the results highlight the interplay of metal electronic structure, coordination-sphere crowding, counterion effects, and ligand preorganization in governing multiligand CO₂ binding.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 17","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Bottom-Up Construction of Many-Electron Relativistic QED Hamiltonian","authors":"Wenjian Liu","doi":"10.1002/qua.70277","DOIUrl":"https://doi.org/10.1002/qua.70277","url":null,"abstract":"<div>\u0000 \u0000 <p>It was shown more than a decade ago [J. Chem. Phys. 139, 014108 (2013)] that a many-electron relativistic quantum electrodynamics (QED) Hamiltonian for high-precision electronic structure calculations can be constructed in a bottom-up fashion, by virtue of charge-conjugated contraction (CCC) of fermion operators when normal-ordering the starting unbounded relativistic Hamiltonian (second-quantized in terms of the electronic Dirac field) with respect to the filled negative-energy Dirac sea of electrons. It is shown here that the same relativistic QED Hamiltonian can also be obtained by equal average of the two relativistic Hamiltonians resulting from the normal-ordering of the starting unbounded relativistic Hamiltonians (second-quantized in terms of the electronic and positronic Dirac fields, respectively) with respect to the filled negative-energy Dirac seas of electrons and positrons, respectively, via the standard contraction of fermion operators. In essence, both procedures incorporate properly the fundamental charge-conjugation symmetry of relativistic quantum mechanics to ensure the symmetric treatment of the electronic and positronic degrees of freedom.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 16","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum Computing and Artificial Neural Network Methods in Approximating the Quantum Many-Body Fermion System for Modern Quantum Chemistry Applications","authors":"Chengze Yang","doi":"10.1002/qua.70271","DOIUrl":"https://doi.org/10.1002/qua.70271","url":null,"abstract":"<p>The field of quantum chemistry has long been defined by the central computational challenge of the quantum many-body fermionic system problem—namely, the electronic Schrödinger equation. The exponential scaling of this equation makes it computationally intractable to solve exactly. As a result, various approximation methods have been developed, ranging from the widely used Density Functional Theory (DFT) to Coupled Cluster (CC) theory. While powerful, these conventional approaches often involve controlled truncations which cause a trade-off between accuracy and computational cost, leaving many systems—particularly those with strong electron correlation—beyond the reach of ab initio simulation. Furthermore, the famous fermionic sign problem is particularly severe in stochastic methods like Quantum Monte Carlo (QMC). Traditional ansatz are also frequently engineered specifically for particular systems, which results in a fragmentation of methodologies and fundamentally limits their transferability. Recent research demonstrates that with carefully designed architectures, ANNs can not only represent ground states of model systems with high precision but also tackle the sign problem, offering a promising path forward for strongly correlated electronic structure calculations. This review charts the paradigm shift driven by Neural Network Quantum States (NNQS), which leverage the representational power of deep learning to overcome these barriers. We detail the architectural evolution from Restricted Boltzmann Machines to autoregressive models like RNNs and Transformers, which enable exact, uncorrelated sampling and bypass critical bottlenecks. The high-efficiency optimization via neural networks was also explored, which decouples optimization cost from model complexity. Furthermore, the frontier of the field is marked by the integration of operator learning and hybrid quantum-classical frameworks, such as Reinforcement Learning for contractive quantum eigen-solvers to generate quantum circuits for simulating many-body molecular systems, and Quantum-Enhanced Neural Networks, which leverage quantum processors to enhance expressivity for hardware-efficient ansatz. By framing the problem through the lens of computational resource allocation and quantum hardware integration—specifically, trading exponential memory demands for polynomial-complexity optimization and sampling—this review elucidates how recent advances at the intersection of artificial neural networks and quantum computing have evolved. The emergence of these methods represents not merely progress toward powerful simulation tools, but also the creation of a hybrid computational interface. This convergence offers a versatile and systematically improvable framework for potentially addressing some of the most challenging problems in quantum physics and chemistry.</p>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 16","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qua.70271","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148696216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Modeling of Ni Cs2 (SO4)2·6H2O Single Crystal Doped With Mn2+ Ion","authors":"Maroj Bharati,&nbsp;Vikram Singh,&nbsp;Ram Kripal","doi":"10.1002/qua.70276","DOIUrl":"https://doi.org/10.1002/qua.70276","url":null,"abstract":"<div>\u0000 \u0000 <p>Crystal field (CF) as well as zero field splitting (ZFS) characteristics of Mn²⁺ in single crystals of Ni Cs₂ (SO₄)₂·6H₂O (NCS) are computationally described utilizing the superposition model (SPM) and angular overlap model (AOM). The ZFS parameters calculated with SPM match the EPR experiment values quite well. The CF energy levels of Mn²⁺: NCS crystals are determined using the crystal field analysis (CFA) tool. Additionally, the experimental and theoretical energy levels agree.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 16","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148696215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}