Journal of Computational Chemistry最新文献

{"title":"Characterization and Computational Engineering of Structural Elements Controlling Gas Permeability in PIP2 ;1 Aquaporins","authors":"Ahmad Raeisi Najafi, Paween Mahinthichaichan, Fraser J. Moss, Ardeschir Vahedi‐Faridi, Walter F. Boron, Emad Tajkhorshid","doi":"10.1002/jcc.70377","DOIUrl":"https://doi.org/10.1002/jcc.70377","url":null,"abstract":"Aquaporins (AQPs) are classical water channels that also conduct small gas molecules such as and across the membrane. The hydrophobic central pore, located at the fourfold symmetry axis of an AQP tetrameric architecture, has been proposed to constitute the most optimal pathway for gas transport, although monomeric water pores can also contribute somewhat to permeation of less hydrophobic species. Here, we report a comparative molecular dynamics (MD) study of gas permeability in a plant AQP and a mammalian AQP1, taking advantage of complementary computational protocols including flooding simulations, umbrella sampling, and implicit ligand sampling. PIP2;1 AQPs, present in plants, are experimentally reported to have lower gas permeability than AQP1, which is present both in plants and animals. Using the spinach PIP2;1 (SoPIP2;1) and bovine AQP1 (bAQP1) as the models, the study unravels the specific structural features controlling the permeability of the central pore to gases. In SoPIP2;1, residue Trp79, which is highly conserved in the plant PIP2;1 family and lines directly the central pore, forms a major constriction region and the main barrier against gas permeation. Notably, the occluding conformation of the four Trp79 residues from the four monomers is stabilized by another conserved residue, Phe207 in the central pore. Sequence and structural comparisons show that both of these residues are replaced by less bulky residues in AQP1, for example, by Leu56 and Ala179, respectively, in bAQP1. The role of Phe207 residues in hindering gas permeation through SoPIP2;1 is confirmed by in silico alanine substitution, which reveals its effect on the local constriction produced by Trp79 residues. Conversely, by mutating Leu56 to tryptophan and Ala179 to phenylalanine in bAQP1, we engineer the protein to a less permeable gas channel.","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"13 1","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147743821","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":"Resource Estimation for VQE on Small Molecules: Impact of Fermion Mappings and Hamiltonian Reductions","authors":"K. S. V. Anurag, Ashish Kumar Patra, Vikas Dattatraya Ghevade, P. Sai Shankar, Ruchika Bhat, V. Raghavendra, Rahul Maitra, G. Jaiganesh","doi":"10.1002/jcc.70379","DOIUrl":"https://doi.org/10.1002/jcc.70379","url":null,"abstract":"Accurate determination of ground-state energies for molecules remains a challenge in quantum chemistry and a cornerstone for progress in fields such as drug discovery and materials design. The Variational Quantum Eigensolver (VQE) represents a leading hybrid quantum-classical paradigm for addressing this challenge; however, its widespread realization is limited by noise and the restricted scalability of current quantum hardware. Achieving efficient simulations on Noisy Intermediate-Scale Quantum (NISQ) devices and forthcoming Fault-Tolerant Application-Scalable Quantum (FASQ) systems demands a detailed understanding of how computational resources scale with molecular complexity and fermion-to-qubit encoding schemes. In this work, resource requirements for VQE implementations employing the Unitary Coupled Cluster Singles and Doubles (UCCSD) ansatz are systematically analyzed. The molecular Hamiltonian is formulated in second quantization and mapped to qubit operators through the Jordan–Wigner (JW), Bravyi–Kitaev (BK), and Parity (Pa) transformations. Hamiltonian reduction strategies, including <span data-altimg=\"/cms/asset/802039db-8dcb-46b8-bace-e6849524bc8c/jcc70379-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"6\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/jcc70379-math-0001.png\"><mjx-semantics><mjx-mrow><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"normal double struck upper Z 2\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c></mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:01928651:media:jcc70379:jcc70379-math-0001\" display=\"inline\" location=\"graphic/jcc70379-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><msub data-semantic-=\"\" data-semantic-children=\"0,1\" data-semantic-role=\"latinletter\" data-semantic-speech=\"normal double struck upper Z 2\" data-semantic-type=\"subscript\"><mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\" mathvariant=\"normal\">ℤ</mi><mn data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\">2</mn></msub></mrow>$$ {mathr","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"20 1","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147732057","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":"Does Aromaticity Drive Metal Cation Binding to Nanographenes? Insights Into Regioselectivity and Cation-\u0000 \u0000 \u0000 π\u0000 \u0000 $$ pi $$\u0000 Bonding","authors":"Omkar Charapale,&nbsp;Sergio Posada-Pérez,&nbsp;Albert Poater,&nbsp;Miquel Solà","doi":"10.1002/jcc.70337","DOIUrl":"10.1002/jcc.70337","url":null,"abstract":"<p>Nanographenes, a subclass of polycyclic aromatic hydrocarbons (PAHs), have attracted significant interest due to their unique electronic properties and broad applications in materials science, optoelectronics, energy storage, and organic chemistry. Here we investigate the interactions of alkali and alkaline-earth metal cations (Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, Ca²⁺) with five D<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow></mrow>\u0000 <mrow>\u0000 <mn>6</mn>\u0000 <mi>h</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {}_{6h} $$</annotation>\u0000 </semantics></math>-symmetric PAHs/nanographenes ranging from benzene to circumcircumcircumcoronene, aiming to elucidate the roles of aromaticity and topology in governing cation binding. We find that cation binding is strongest at the most aromatic peripheral six-membered rings. Energy decomposition analysis reveals that binding is dominated by orbital interactions rather than electrostatics, with Be²⁺ displaying anomalous, strongly covalent character and minimal ionic contribution. We introduce a novel ring-based reactivity descriptor combining the Fukui function and electronic delocalization, which accurately predicts binding energies. In addition, a local topological indicator shows a strong correlation with cation–PAH interactions and enables reliable predictions for graphene. Overall, our results demonstrate that aromaticity alone does not govern cation binding, but its interplay with local reactivity and topology is decisive, providing a unified framework that bridges chemical topology and computational chemistry.</p>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcc.70337","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147669424","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":"Inconsistencies of Gaussian's “NBO 3.1” Module With Authentic Natural Population Analysis","authors":"Frank Weinhold","doi":"10.1002/jcc.70374","DOIUrl":"10.1002/jcc.70374","url":null,"abstract":"<p>We provide illustrative examples of the discrepancies between “NBO analysis results” as obtained from <i>Gaussian-16</i>'s proprietary <i>NBO 3.1</i> module versus the authentic <i>Natural Bond Orbital</i> program as first developed in the 1980s and maintained in the current <i>NBO7</i> program version.</p>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcc.70374","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147663929","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":"Efficient Machine Learning Prediction of Solvent-Dependent \u0000 \u0000 \u0000 \u0000 \u0000 \u0000 1\u0000 \u0000 \u0000 H\u0000 \u0000 $$ {}^1mathrm{H} $$\u0000 NMR Chemical Shifts in Zinc Complexes","authors":"Jyothika R. Pillay,&nbsp;Michael Ringleb,&nbsp;Alexander Croy,&nbsp;Stefan Zechel,&nbsp;Ulrich S. Schubert,&nbsp;Stefanie Gräfe","doi":"10.1002/jcc.70368","DOIUrl":"10.1002/jcc.70368","url":null,"abstract":"&lt;p&gt;Accurate prediction of NMR chemical shifts in transition metal complexes remains challenging due to the wide range of coordination environments and complex electronic structures of these systems. In this work, we present a machine learning approach (ML) for rapid and accurate prediction of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;&lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mtext&gt;H&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {}^1mathrm{H} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; NMR shifts in zinc complexes across multiple solvent environments. We systematically selected a diverse set of zinc complexes from the transition metal quantum mechanics (tmQM) database using K-means clustering on SOAP descriptors, and performed DFT NMR calculations across five solvents to generate training data. We combine smooth overlap of atomic positions (SOAP) descriptors with tree-based ensemble methods to predict proton chemical shifts. Among several ML algorithms evaluated, LightGBM achieved the best performance on held-out test complexes (MAE = 0.016 ppm, RMSE = 0.028 ppm, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}^2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 0.99), demonstrating excellent generalization to unseen molecular structures. External validation against experimental NMR data across multiple solvents revealed strong predictive performance (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}^2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 0.90, MAE = 0.56 ppm), with exceptional accuracy in methanol (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}^2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 0.96) and acetonitrile (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 ","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcc.70368","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147663663","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":"Aromaticity-Induced Spin State Switching and High-Spin States in Non-Alternant Polyradicals","authors":"Sergi Betkhoshvili,&nbsp;Ibério de P. R. Moreira,&nbsp;Jordi Poater,&nbsp;Josep Maria Bofill","doi":"10.1002/jcc.70366","DOIUrl":"10.1002/jcc.70366","url":null,"abstract":"<p>We present fully <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>π</mi>\u0000 </mrow>\u0000 <annotation>$$ pi $$</annotation>\u0000 </semantics></math>-conjugated non-alternant systems, including cases where a topologically tailored degree of freedom expands the set of possible favored spin states. This leads to the possibility of switching the lowest-energy spin state upon a specific geometric distortion. Increasing the delocalization energy in specific electronic configurations via including more (pro)aromatic rings in the polyradical(oid) system without changing the topology can induce a high-spin ground state (GS). The peculiar topology of the presented non-alternant <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>π</mi>\u0000 </mrow>\u0000 <annotation>$$ pi $$</annotation>\u0000 </semantics></math>-systems, which has a commensurate effect on GS electronic structure and spin spectrum, usually leading to greater stabilization of open-shell character, is potentially useful for novel compounds with previously unrealized properties for organic electronics, spintronics, biosensors, single-molecule devices, etc. The proposed polyradicals, with one of its derivatives recently synthesized and characterized as a triplet GS diradical, are rationally designed to minimize strain and steric hindrance to make them synthetically accessible and thermodynamically stable, and can be kinetically stabilized by bulky protecting groups at exposed radical sites.</p>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcc.70366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147663928","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":"Quantum Interference and Aromaticity Control in Triazine-Based Molecular Junctions: A Combined Green's Function and Density Functional Theory Study","authors":"Sergio Moles Quintero,&nbsp;Artur Brotons-Rufes,&nbsp;Irene Casademont-Reig,&nbsp;Albert Poater,&nbsp;Miquel Solà,&nbsp;Sergio Posada-Pérez,&nbsp;Mercedes Alonso","doi":"10.1002/jcc.70371","DOIUrl":"10.1002/jcc.70371","url":null,"abstract":"<div>\u0000 \u0000 <p>Molecular electronics provides a powerful platform to explore quantum transport phenomena at the single-molecule level, where charge transport is governed by molecular structure, connectivity, and electronic delocalization. In this work, we present a comprehensive computational study of electron transport through triazine-based molecular junctions inspired by graphitic carbon nitride motifs. Using a bottom-up approach, we investigate a hierarchy of molecular models ranging from triazine monomers to heptazine and tri-heptazine scaffolds. Electron transport properties are analyzed within the nonequilibrium Green's function formalism combined with density functional theory (DFT), focusing on transmission spectra, local transmission pathways, and quantum interference effects. We show that nitrogen-rich conjugated frameworks exhibit a rich variety of interference patterns, including constructive, destructive, and shifted destructive quantum interference, which are highly sensitive to molecular connectivity and substitution patterns. Orbital selection rules and pathway analyses are employed to rationalize the emergence and position of interference features. Furthermore, we demonstrate that substituent effects modulate molecular conductance in a topology-dependent manner, and that changes in electronic delocalization, quantified through aromaticity descriptors such as HOMA, MCI, AV1245, and AV_min, correlate with transmission behavior. In extended triazine-based architectures, the interplay between competing transmission pathways leads to nontrivial aromaticity–conductance relationships.</p>\u0000 </div>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147663957","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":"Direct Energy Gap Calculations in Heisenberg Spin Systems Using Superconducting Quantum Devices","authors":"Boni Paul,&nbsp;Sudhindu Bikash Mandal,&nbsp;Kenji Sugisaki,&nbsp;Bhanu Pratap Das","doi":"10.1002/jcc.70355","DOIUrl":"10.1002/jcc.70355","url":null,"abstract":"<div>\u0000 \u0000 <p>Accurate calculation of spin-state energy gaps is central to spin chemistry. The novel Quantum Phase Difference Estimation (QPDE) algorithm enables direct computation of energy gaps on a quantum computer. However, the required quantum circuits are typically too deep for noisy intermediate-scale quantum (NISQ) devices. In this study, as an initial step toward practical calculations for strongly correlated molecular multi-spin systems, we applied QPDE to two- and three-spin Heisenberg Hamiltonians with various geometries and coupling strengths, including symmetric, asymmetric, spin-frustrated, and non-frustrated configurations. We found that the quantum circuit for the time-evolution operator achieves constant depth due to its match gate-like structure, making it well-suited for NISQ implementation. Proof-of-principle hardware demonstrations using an IBM quantum processor yielded 85%–96% accuracy in determining spin-state energy gaps.</p>\u0000 </div>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147655657","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":"Revisiting the Maximum Hardness Principle: A Quantitative Analysis on Reaction Datasets","authors":"Ashima Bajaj,&nbsp;Farnaz Heidar-Zadeh,&nbsp;Thijs Stuyver,&nbsp;Scott Habershon,&nbsp;Paul W.Ayers,&nbsp;Frank De Proft","doi":"10.1002/jcc.70365","DOIUrl":"10.1002/jcc.70365","url":null,"abstract":"<div>\u0000 \u0000 <p>Chemical hardness is one of the fundamental concepts in chemical reactivity theory, rigorously defined within the framework of Conceptual Density Functional Theory (CDFT). The associated maximum hardness principle (MHP), which postulates that a favorable direction of reaction is toward the state of maximum hardness, has been widely applied as a guiding rule to govern the direction of chemical reactions. However, several studies have questioned its validity. In this work, we investigated the quantitative applicability of the MHP using two reaction datasets, viz, a dipolar cycloaddition dataset of 5269 reaction profiles and the more comprehensive BH9 dataset of 449 reactions. We adopted different approximations to compute the hardness, including Kohn–Sham orbital based frontier molecular orbital (FMO) and the finite difference approximation (FDA). The effect of using different definitions to compute the average hardness of bimolecular reactions is analyzed on the validity of MHP. Our analysis revealed dependence of hardness values on the level of theory, definitions and approximations used which should be kept in mind before criticizing the MHP. Among 5269 cycloaddition reactions, approximately 80% of the reactions are found to obey the MHP. For BH9 dataset, MHP is found to better supported for unimolecular reactions, while remaining strongly dependent on the definition used to compute the average hardness for bimolecular reactions. Reactions in which the individual hardness of the reactants differs significantly are more likely to disobey MHP. Nonetheless, since these electronic structure principles are qualitative in nature, their validity cannot be expected to be universal.</p>\u0000 </div>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147630768","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":"Spectroscopic Investigation of Thioacrolein by Variational and Perturbational Approaches","authors":"Guntram Rauhut","doi":"10.1002/jcc.70343","DOIUrl":"10.1002/jcc.70343","url":null,"abstract":"<p>The vibrational spectra of <i>trans</i> and <i>cis</i>-thioacrolein have been studied by 2nd order vibrational perturbation theory (VPT2) and vibrational configuration interaction (VCI) theory. All calculations rely on multilevel potential energy surfaces (PESs) with the highest level being explicitly correlated coupled-cluster theory including single and double excitation and a perturbational treatment of the triple excitation in combination with an augmented triple-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ζ</mi>\u0000 </mrow>\u0000 <annotation>$$ zeta $$</annotation>\u0000 </semantics></math> basis set. Comparisons with experimental data are provided, including a number of predictions for unobserved fundamentals. Moreover, (ro) vibrational configuration interaction (RVCI) theory has been used for the simulation of the microwave spectrum, accompanied by the calculation of spectroscopic constants from perturbation theory.</p>","PeriodicalId":188,"journal":{"name":"Journal of Computational Chemistry","volume":"47 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcc.70343","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147630425","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}