International Journal of Quantum Chemistry最新文献

{"title":"Isotope Effects on H2O, OH, and H Adsorption on Pd(111): Insights From Combined Plane Wave and Localized Basis Set Calculations","authors":"Ren Yamaoka,&nbsp;David S. Rivera Rocabado,&nbsp;Yusuke Kanematsu,&nbsp;Takayoshi Ishimoto","doi":"10.1002/qua.70266","DOIUrl":"https://doi.org/10.1002/qua.70266","url":null,"abstract":"<p>Understanding the effects of hydrogen/deuterium isotopes on catalytic metal surfaces is crucial for catalyst design and isotope-labelling strategies. We investigate H₂O, OH, and H adsorption on Pd(111) using the combined plane wave and localized basis set (CPLB) scheme, which incorporates nuclear quantum effects within density functional theory. Our results display a tendency toward stronger adsorption for deuterated species relative to their hydrogen analogues, indicating enhanced thermodynamic stability upon deuteration. Additionally, isotopic substitution induces geometric shifts, including longer adsorbate–surface distances and subtle bond length changes. A comparison with Pt(111) literature data suggests that the metal identity may exert a more pronounced influence during dissociation than during the initial adsorption. This CPLB approach enables the quantification of nuclear quantum effects in surface chemistry with accuracy and computational efficiency. These capabilities offer new opportunities to assess isotope effects in catalysis, providing relevance for isotope-labelling applications and the design of improved catalytic processes.</p>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 15","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qua.70266","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615725","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":"Energy and Planarity in Boron-Nitrogen Fulvene Isomers: A Quantum-Chemical and QSPR Study","authors":"Gustavo E. Massaccesi,&nbsp;Pablo R. Duchowicz,&nbsp;Diego R. Alcoba,&nbsp;Ofelia B. Oña,&nbsp;Luis Lain,&nbsp;Alicia Torre,&nbsp;David L. Cooper,&nbsp;Josep M. Oliva-Enrich","doi":"10.1002/qua.70264","DOIUrl":"https://doi.org/10.1002/qua.70264","url":null,"abstract":"<p>Quantum-chemical computations at the M06-2X/def2TZVP level of theory are used to determine the minimum energy geometries and relative energies of all of the boron-nitrogen fulvene isomers that correspond to sequential isoelectronic replacements in fulvene of the type {CC ↔ BN}. Compact Quantitative Structure–Property Relationships (QSPR) regression and classification models for the energetics and planarity/nonplanarity of these isomers are developed using structural molecular descriptors of the fragment type that involve atom types and the connectivity pattern. It is shown that the energies of the boron-nitrogen fulvene isomers can be reproduced/predicted with just four structural descriptors, namely the numbers of C, CCH, NN, and BBH fragments, with a root mean square error in the energy of 0.019 au and with a coefficient of determination of 0.9999 for the training set. In addition, the classification of the molecules into planar or nonplanar structures achieves an average sensitivity of 0.9583 for calibration when using only three descriptors: the numbers of BNNB, BBCNH, and NN fragments.</p>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 15","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qua.70264","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148534248","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 Crystallography: X-Ray Orbitals Are Kohn–Sham Orbitals","authors":"Chérif F. Matta,&nbsp;Lou Massa","doi":"10.1002/qua.70242","DOIUrl":"https://doi.org/10.1002/qua.70242","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;It is suggested that, under restrictive ideal circumstances, the interacting electronic energy of a system can be obtained directly from experimentally accessible x-ray orbitals, defined here as orbitals obtained from direct fitting of the one-body density matrix to measured x-ray structure factors, through inverse Kohn–Sham equation functional integration. The argument rests on the identity, within a unitary transformation, between experimentally fitted x-ray orbitals and theoretically calculated Kohn–Sham orbitals, both of which—in ideal circumstances—yield the same electron density. Using x-ray orbitals, one may evaluate both the Kohn–Sham kinetic energy and the interacting potential energy by functional integration of the exact Kohn–Sham potential, taken directly from the Kohn–Sham equations, expressed in atomic units (a.u.), &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ε&lt;/mi&gt;\u0000 &lt;mtext&gt;HOMO&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;mfrac&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mfrac&gt;\u0000 &lt;mfrac&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt;∇&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ϕ&lt;/mi&gt;\u0000 &lt;mtext&gt;HOMO&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;ϕ&lt;/mi&gt;\u0000 &lt;mtext&gt;HOMO&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mfrac&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {v}_sleft(mathbf{r}right)={varepsilon}_{mathrm{HOMO}}+frac{1}{2}frac{nabla^2{phi}_{mathrm{HOMO}}left(mathbf{r}right)}{phi_{mathrm{HOMO}}left(mathbf{r}right)} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. This approach allows the total interacting Kohn–Sham energy: &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mi&gt;KS&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mrow&gt;\u0000 ","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 15","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148534254","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":"A Non-Born Oppenheimer Description of Molecular Angular Momentum","authors":"S. A. Alexander,&nbsp;R. L. Coldwell","doi":"10.1002/qua.70262","DOIUrl":"https://doi.org/10.1002/qua.70262","url":null,"abstract":"<div>\u0000 \u0000 <p>We use variational Monte Carlo methods to optimize fully nonadiabatic trial wavefunctions that describe the <i>J</i> = 0, 1, 2, and 3 rotational states of H₂⁺ (Ψ_0J). Our results show that a prefactor that depends on the molecular center of mass yields energies that are in excellent agreement with previous calculations. When we use these trial wavefunctions to evaluate the angular momentum expectation values &lt;Ψ_0J|L²|Ψ_0J&gt; and &lt;Ψ_0J|L_z|Ψ_0J&gt;, we find that they are eigenfunctions of these operators. We have also evaluated these expectation values for the individual particles in this molecule, and our results show that the electron provides a significant amount of the molecule's angular momentum and that this amount changes for each rotational state.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 15","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148533422","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":"Tuning Two-Photon Absorption Property of A-π-A Type Cyanine Dyes in NIR Region via π-Electron Structure","authors":"Jia Wei,&nbsp;Lanping Wang,&nbsp;Bingyan Chen,&nbsp;Linpo Yang,&nbsp;Yuanzuo Li,&nbsp;Yinglin Song","doi":"10.1002/qua.70263","DOIUrl":"https://doi.org/10.1002/qua.70263","url":null,"abstract":"<div>\u0000 \u0000 <p>This study systematically investigates four A-π-A cyanine dyes using density functional theory (DFT) and the sum-over-states (SOS) model to reveal how increasing π-delocalization affects near-infrared (NIR) two-photon absorption (TPA) performance. Theoretical results show that extending the π-plane broadens the conjugated system, enhances π-electron delocalization, and reduces the extent of orbital overlap. The designed dye 3T-2 shows prominent localized excitation in the two-photon transition process. It possesses a specific and concentrated transition pathway, which effectively elevates the transition dipole moments. Consequently, 3T-2 exhibits excellent TPA properties in the NIR region, with a TPA cross section of 129779.9 GM at 784.4 nm and a third-order nonlinear coefficient of 44462.8 × 10⁻³⁶ esu. It is anticipated that this study offers robust theoretical support for the modulation of nonlinear optical performances in A-π-A type NIR dyes, which further facilitates the practical implementation in multiphoton bioimaging and other related fields.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 14","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148533727","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":"First-Principles Study of the Electronic Properties and NOx (x = 1,2) Adsorption Characteristics of Al and Cr Doped CdS Materials","authors":"Xiaohan Hui,&nbsp;Deming Ma,&nbsp;Sihan Guo,&nbsp;Rujun Liu,&nbsp;Cong Zhao,&nbsp;Kun Ma,&nbsp;Yang Shen,&nbsp;Zhen Cui,&nbsp;Enling Li","doi":"10.1002/qua.70261","DOIUrl":"https://doi.org/10.1002/qua.70261","url":null,"abstract":"<div>\u0000 \u0000 <p>This study uses first-principles calculations to investigate the structural, electronic, and NOx adsorption properties of monolayer CdS. The results show that pristine CdS is a direct-bandgap semiconductor with a bandgap of 1.628 eV, while Al and Cr doping induce an indirect bandgap and enhance charge transfer. In addition, Cr-doped CdS exhibits a magnetic moment of 4.00 μ_B. Doping significantly strengthens the interaction between CdS and gas molecules. For NO adsorption, the adsorption height decreases from 3.0 Å (pristine) to 1.894 Å (Al-CdS) and 1.644 Å (Cr-CdS), with corresponding adsorption energies of −1.670 eV and −2.470 eV, respectively. For NO₂ adsorption, the adsorption height is 1.966 Å (Al-CdS) and 1.959 Å (Cr-CdS), with adsorption energies of −2.794 eV and −2.067 eV, respectively, indicating stronger binding compared to the pristine system. Bader charge analysis further quantifies the charge-transfer behavior, revealing net charge transfers of 0.648 |e| (Al-CdS) and 0.501 |e| (Cr-CdS) for NO adsorption, and 0.849 |e| (Al-CdS) and 0.624 |e| (Cr-CdS) for NO₂ adsorption, confirming that both NO and NO₂ act as strong electron acceptors. The formation of N<span></span>Al and N<span></span>Cr bonds further enhances the adsorption strength. These results demonstrate that Al- and Cr-doped CdS monolayers exhibit significantly improved gas adsorption performance, with larger absolute adsorption energies indicating stronger gas–surface interactions, which are crucial for enhancing gas capture and sensing-related properties.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 14","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148533728","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":"Chlorpyrifos and Chlorpyrifos-Methyl Degradation by ˙OH in the Atmosphere and in Water: Theoretical Calculations and Molecular Dynamic Simulations","authors":"Mengjiao Liu,&nbsp;Yuquan Zhu,&nbsp;Rufang Zhao,&nbsp;Zia UI Haq Khan,&nbsp;Jingyu Sun","doi":"10.1002/qua.70257","DOIUrl":"https://doi.org/10.1002/qua.70257","url":null,"abstract":"<div>\u0000 \u0000 <p>As agriculture advances, organophosphorus pesticides (OPPs), renowned for their efficacy, are being extensively utilized. However, their residues pose significant risks to both the environment and human health. In this study, we employed computational methods in both gas and aqueous phases to investigate the ˙OH-initiated oxidation mechanisms of two common pesticides, chlorpyrifos (CPY) and chlorpyrifos-methyl (CPM). The calculations revealed that the reactions proceed primarily via addition and dehydrogenation. Addition at the phosphorus atom was found to be the most energetically favorable pathway, surpassing additions at the pyridine ring carbon atoms, followed by hydrogen abstraction from the methyl or ethyl group. In contrast, other abstraction reactions were less favorable. The reaction rate constants, atmospheric lifetimes, and half-lives were calculated. Acute and chronic toxicity assessments were performed to estimate the toxicity levels of CPM and its degradation products. The neurotoxicity of these products was further investigated using molecular docking and molecular dynamics simulations. Compounds P15 and P26 exhibited the highest binding affinities with acetylcholinesterase (AChE), while P24 and P26 showed the strongest binding to butyrylcholinesterase (BChE). Finally, molecular dynamics simulations over a 100 ns timeframe demonstrated stable interactions between CPM degradation products and cholinesterases, identifying the degradation products that pose the greatest risk to the neurodevelopmental system. These results could provide theoretical support for the ˙OH-initiated degradation of OPPs in engineering applications and are conducive to the development of new OPPs.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 14","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148533063","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":"From Near-Metallic to Wide-Gap Semiconductors: Elastic Resilience and Record Hydrogen Densities in Tetragonal A2BH4 (A = Li, Na; B = Be, Mg) From DFT and Molecular Dynamics","authors":"Mohamed El Amine El Goutni,&nbsp;Hela Ferjani,&nbsp;Mohammed Batouche,&nbsp;Taieb Seddik,&nbsp;Yasmeen G. Abou El-Reash,&nbsp;Mohamed Houcine Dhaou","doi":"10.1002/qua.70260","DOIUrl":"https://doi.org/10.1002/qua.70260","url":null,"abstract":"<div>\u0000 \u0000 <p>Tetragonal A₂BH₄ (A = Li, Na; B = Be, Mg) hydrides adopting the P4₂/mnm space group were systematically investigated using full-potential density functional theory within GGA-WC and HSE06 frameworks, complemented by phonon dispersion analysis and ab initio molecular dynamics simulations, to evaluate their structural stability, mechanical resilience, electronic character, and hydrogen storage performance. All four compounds satisfy Born–Huang elastic stability criteria and exhibit universal ductile behavior with Pugh ratios of 1.757–1.962, positive Cauchy pressures of 14.69–29.05 GPa, and near-perfect elastic isotropy, collectively ensuring structural integrity under cyclic hydrogen loading. In marked contrast to boron-centered analogues, the divalent alkaline-earth B-site chemistry produces a compositionally tunable semiconducting series with HSE06 band gaps spanning 0.19 eV for Li₂BeH₄ to 2.15 eV for Na₂MgH₄, driven by systematic A-site lattice expansion and B-site covalency reduction. Formation enthalpies of −42.61 to −46.82 kJ/mol H₂ and desorption temperatures of 316–347 K confirm thermodynamically optimal near-ambient hydrogen release for all compositions. Li₂BeH₄ achieves an outstanding gravimetric capacity of 14.97 wt% exceeding the DOE target by 130% alongside a volumetric density of 81.59 kg H₂/m³. All four compounds simultaneously satisfy DOE volumetric benchmarks, positioning this family as exceptional multifunctional candidates for next-generation solid-state hydrogen storage.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 13","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386655","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":"Sodium Storage Mechanism and Electrochemical Properties of Various P-Doped Graphenes for Anode Materials in Sodium-Ion Batteries","authors":"Jiyang Zhang,&nbsp;Xu Zhang,&nbsp;Jiapeng Zhu,&nbsp;Chaoyang Huang,&nbsp;Bingchen Zhang,&nbsp;Wenxue Song,&nbsp;Jihong Liu,&nbsp;Guixiao Jia,&nbsp;Dawei Lan","doi":"10.1002/qua.70254","DOIUrl":"https://doi.org/10.1002/qua.70254","url":null,"abstract":"<div>\u0000 \u0000 <p>Heteroatom doping is an effective approach to enhance sodium storage capacities of carbon materials. In this study, we synthesized P-doped porous carbon (C–P) materials with defects derived from lignite humic residues. The effects of introduced P, O, vacancy defects and combinations of these defects on Na storage capacities have been investigated using a combination method of density functional theory (DFT) calculations and experiments. Binding energies, geometrical and electronic structures of Na on graphene surfaces with various defects are calculated. The results indicate that the introduction of defects, particularly P-dopings, enhances the interaction between graphene and Na, improving the sodium storage capacity of the graphene. This is attributed to increased density of states of the modified graphenes at the Fermi level and strong covalent interaction between Na and P. These results are supported by experimental data, highlighting the role of the P-doping in improving sodium storage. Experimental studies demonstrate that P-doped porous carbon (C–P) with possible common defects such as O-adsorbed, P-doped, vacancy defects and combinations of these defects exhibits a reversible specific capacity of 179.5 mAh g⁻¹ with over 90% capacity retention after 150 cycles at a current density of 0.1 A g⁻¹, and maintain a reversible specific capacity of 147.4 mAh g⁻¹ after 1500 cycles at 1.0 A g⁻¹, superior to other analogous materials.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 13","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386327","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":"Photochemical and Conformational Analyses of Chlorophyll a: Contribution of the Phytol Chain in the Absorption Spectrum","authors":"Yamil Hernández-Urquieta,&nbsp;Joaquín Barroso-Flores,&nbsp;María Eugenia Castro,&nbsp;Francisco J. Melendez","doi":"10.1002/qua.70251","DOIUrl":"https://doi.org/10.1002/qua.70251","url":null,"abstract":"<div>\u0000 \u0000 <p>Chlorophyll <i>a</i> has been extensively studied due to its role as the primary pigment responsible for oxygenic photosynthesis. However, the complexity of the molecule has led many theoretical studies to simplify its structure, often removing the phytol chain—a hydrocarbon tail—under the assumption that it does not alter the photochemical properties of chlorophyll. To achieve more accurate results, it is essential to determine whether the phytol chain influences key photochemical properties, such as the absorption spectrum. In this work, we conducted a conformational study of chlorophyll <i>a</i> to determine the most populated conformer using Density Functional Theory (DFT) calculations. We investigate the influence of the phytol chain on the coordination interactions between nitrogen atoms and the magnesium ion, as well as its impact on vertical excitation using the Time-Dependent DFT (TD-DFT) approach. Our results demonstrate that the phytol chain contributes slightly to all excited states. These findings underscore the role of the complete molecular structure in vacuum and introduce critical inquiries regarding the phytol chain relevance in more complex environments.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"126 13","pages":""},"PeriodicalIF":2.7,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386328","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}