Pub Date : 2026-01-08DOI: 10.1016/j.comptc.2026.115666
Zhifeng Li , Xiao Ru , Zijing Lin
Computational prediction of peptide structures and conformational stability remains challenging due to their inherent structural flexibility. Existing ensemble sampling methods often lack accuracy or computational efficiency. In this study, we develop a robust computational framework for accurately predicting peptide structures and qualitatively assessing their conformational stability using kernel density estimation of the equilibrium free-energy landscape. We introduce an enhanced ensemble sampling strategy based on three-fragment splicing, replacing conventional two-fragment assembly. Validated across multiple short peptide systems, our method predicts experimental structures with accuracy comparable to AI-based techniques and surpasses pure force-field methods, and achieves superior conformational stability prediction over alternative ensemble sampling approaches. The results suggest that this work establishes a computationally efficient and accurate framework for peptide structure and structural stability prediction, offering significant promise for peptide engineering and rational drug design.
{"title":"Decoding peptide structures and structural stability via conformational ensemble searching","authors":"Zhifeng Li , Xiao Ru , Zijing Lin","doi":"10.1016/j.comptc.2026.115666","DOIUrl":"10.1016/j.comptc.2026.115666","url":null,"abstract":"<div><div>Computational prediction of peptide structures and conformational stability remains challenging due to their inherent structural flexibility. Existing ensemble sampling methods often lack accuracy or computational efficiency. In this study, we develop a robust computational framework for accurately predicting peptide structures and qualitatively assessing their conformational stability using kernel density estimation of the equilibrium free-energy landscape. We introduce an enhanced ensemble sampling strategy based on three-fragment splicing, replacing conventional two-fragment assembly. Validated across multiple short peptide systems, our method predicts experimental structures with accuracy comparable to AI-based techniques and surpasses pure force-field methods, and achieves superior conformational stability prediction over alternative ensemble sampling approaches. The results suggest that this work establishes a computationally efficient and accurate framework for peptide structure and structural stability prediction, offering significant promise for peptide engineering and rational drug design.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1257 ","pages":"Article 115666"},"PeriodicalIF":3.0,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923700","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}
Pub Date : 2026-01-06DOI: 10.1016/j.comptc.2026.115658
Yuxi Du , Yali Tuo , Changcheng Chen , Yaxin Xu , Zhengjun Wang , Zhao Han , Xiongfei Yun , Jiangzhou Xie , Shuli Gao , Wen Chen , Xiaoning Guan , Gang Liu , Pengfei Lu
In this work, first-principles calculations were systematically used to investigate the electronic structure, mechanical properties, and optical behavior of lead- double perovskite Cs₂AgSbX₆ (X = Cl, Br, I) under the biaxial strain from −4 % to 4. The results show that the strain modulates the anti-bonding characteristics of the valence band maximum and the conduction band minimum, leading to a linear increase (decrease) in bandgap under tensile (compressive) strain. The materials exhibit strain-responsive behavior within the studied strain range. Notably, the compressive strain (−4 %, −%) significantly reduces the hole effective mass in Cs₂AgSbCl₆, thereby enhancing carrier mobility and increasing the Young's modulus, indicating that the atomic interactions are strengthened In contrast, tensile strain (2 %, 4 %) reduces the modulus and increases the structural flexibility, weakening the orbital coupling and causing a widening of the bandgap a blue shift of the absorption edge. These findings provide theoretical insights into strain engineering for optimizing the properties of double perovskite materials. In the context of photovolta and hydrogen applications, the improved bandgap value of the material under compressive strain has an impact on the carrier transport and light absorption performance; for flexible devices, precise strain control (2 %) enables the synergistic optimization of photoelectric performance and mechanical reliability. This work elucidates the strain-dependent structure-performance relationship in lead-free double perskites and provides new perspectives on their applications in green energy and flexible electronics.
{"title":"Strain-tuning the optoelectronic and mechanical properties of Cs₂AgSbX₆ (X = Cl, Br, I): A combined computational study of electronic structure and property underpinnings","authors":"Yuxi Du , Yali Tuo , Changcheng Chen , Yaxin Xu , Zhengjun Wang , Zhao Han , Xiongfei Yun , Jiangzhou Xie , Shuli Gao , Wen Chen , Xiaoning Guan , Gang Liu , Pengfei Lu","doi":"10.1016/j.comptc.2026.115658","DOIUrl":"10.1016/j.comptc.2026.115658","url":null,"abstract":"<div><div>In this work, first-principles calculations were systematically used to investigate the electronic structure, mechanical properties, and optical behavior of lead- double perovskite Cs₂AgSbX₆ (X = Cl, Br, I) under the biaxial strain from −4 % to 4. The results show that the strain modulates the anti-bonding characteristics of the valence band maximum and the conduction band minimum, leading to a linear increase (decrease) in bandgap under tensile (compressive) strain. The materials exhibit strain-responsive behavior within the studied strain range. Notably, the compressive strain (−4 %, −%) significantly reduces the hole effective mass in Cs₂AgSbCl₆, thereby enhancing carrier mobility and increasing the Young's modulus, indicating that the atomic interactions are strengthened In contrast, tensile strain (2 %, 4 %) reduces the modulus and increases the structural flexibility, weakening the orbital coupling and causing a widening of the bandgap a blue shift of the absorption edge. These findings provide theoretical insights into strain engineering for optimizing the properties of double perovskite materials. In the context of photovolta and hydrogen applications, the improved bandgap value of the material under compressive strain has an impact on the carrier transport and light absorption performance; for flexible devices, precise strain control (2 %) enables the synergistic optimization of photoelectric performance and mechanical reliability. This work elucidates the strain-dependent structure-performance relationship in lead-free double perskites and provides new perspectives on their applications in green energy and flexible electronics.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1257 ","pages":"Article 115658"},"PeriodicalIF":3.0,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903997","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}
Pub Date : 2026-01-06DOI: 10.1016/j.comptc.2026.115660
Lien Le , Hoan Nguyen
Confined monolayer water exhibits a hexagonal ice phase with p6mm symmetry and intrinsic proton disorder. We derive an exact residual entropy for this phase by mapping its hydrogen-bond network to an integrable vertex model. Pairing inequivalent oxygen sites into effective four-coordinated vertices yields a five-vertex model with a dual six-vertex representation and exactly computable freeenergy density. When dangling OH bonds fluctuate among symmetry-equivalent orientations, additional degeneracies increase the residual entropy to . These results clarify how in-plane ice rules constrain the hydrogen-bond network, while out-of-plane dangling-bond fluctuations provide additional configurational degeneracy that governs disorder in interfacial and nanoconfined water.
{"title":"Residual entropy of confined and interfacial monolayer water ice","authors":"Lien Le , Hoan Nguyen","doi":"10.1016/j.comptc.2026.115660","DOIUrl":"10.1016/j.comptc.2026.115660","url":null,"abstract":"<div><div>Confined monolayer water exhibits a hexagonal ice phase with p6mm symmetry and intrinsic proton disorder. We derive an exact residual entropy for this phase by mapping its hydrogen-bond network to an integrable vertex model. Pairing inequivalent oxygen sites into effective four-coordinated vertices yields a five-vertex model with a dual six-vertex representation and exactly computable freeenergy density. When dangling OH bonds fluctuate among symmetry-equivalent orientations, additional degeneracies increase the residual entropy to <span><math><mfrac><mi>S</mi><msub><mi>k</mi><mi>B</mi></msub></mfrac><mo>=</mo><mn>0.820051</mn></math></span>. These results clarify how in-plane ice rules constrain the hydrogen-bond network, while out-of-plane dangling-bond fluctuations provide additional configurational degeneracy that governs disorder in interfacial and nanoconfined water.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1257 ","pages":"Article 115660"},"PeriodicalIF":3.0,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974358","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}
Pub Date : 2026-01-02DOI: 10.1016/j.comptc.2026.115657
Regina M. Burganova , Zafari Umar , Ilya V. Chepkasov , Hayk Zakaryan , Irina I. Piyanzina
Rare-earth trifluoride nanoparticles attract increasing attention due to their potential use in biomedical applications and spintronics, where understanding the correlation between structure and magnetic properties is crucial. However, experimental determination of these properties at the nanoscale remains challenging. In this work, the structures and magnetic characteristics of (DyF) (–10) nanoclusters were predicted and analyzed using an evolutionary algorithm combined with density functional theory. This study reveals how nanoclusters evolve structurally from symmetric monomers (C) to less symmetric larger clusters (C1), with Dy-F bonds (2.02–2.96 Å), Dy-Dy distances (3.43–8.42 Å), and coordination numbers increasing from 3 to 8. Notably, magnetic moments grow with size, peaking near at , while spin compensation emerges at . Incorporating spin–orbit coupling highlights significant magnetic anisotropy energies up to 245 meV. Additionally, solvent effects provide substantial stabilization ( to eV). These findings uniquely link structural changes to size-dependent magnetic properties, advancing predictive design of rare-earth fluoride nanomaterials.
{"title":"Towards structure-property prediction in DyF3 nanoclusters","authors":"Regina M. Burganova , Zafari Umar , Ilya V. Chepkasov , Hayk Zakaryan , Irina I. Piyanzina","doi":"10.1016/j.comptc.2026.115657","DOIUrl":"10.1016/j.comptc.2026.115657","url":null,"abstract":"<div><div>Rare-earth trifluoride nanoparticles attract increasing attention due to their potential use in biomedical applications and spintronics, where understanding the correlation between structure and magnetic properties is crucial. However, experimental determination of these properties at the nanoscale remains challenging. In this work, the structures and magnetic characteristics of (DyF<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> (<span><math><mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow></math></span>–10) nanoclusters were predicted and analyzed using an evolutionary algorithm combined with density functional theory. This study reveals how nanoclusters evolve structurally from symmetric monomers (C<span><math><msub><mrow></mrow><mrow><mn>3</mn><mi>v</mi></mrow></msub></math></span>) to less symmetric larger clusters (C<sub>1</sub>), with Dy-F bonds (2.02–2.96<!--> <!-->Å), Dy-Dy distances (3.43–8.42<!--> <!-->Å), and coordination numbers increasing from 3 to 8. Notably, magnetic moments grow with size, peaking near <span><math><mrow><mo>≈</mo><mn>45</mn><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></mrow></math></span> at <span><math><mrow><mi>n</mi><mo>=</mo><mn>10</mn></mrow></math></span>, while spin compensation emerges at <span><math><mrow><mi>n</mi><mo>=</mo><mn>7</mn></mrow></math></span>. Incorporating spin–orbit coupling highlights significant magnetic anisotropy energies up to 245<!--> <!-->meV. Additionally, solvent effects provide substantial stabilization (<span><math><mrow><mo>−</mo><mn>2</mn><mo>.</mo><mn>8</mn></mrow></math></span> to <span><math><mrow><mo>−</mo><mn>8</mn><mo>.</mo><mn>2</mn></mrow></math></span> <!--> <!-->eV). These findings uniquely link structural changes to size-dependent magnetic properties, advancing predictive design of rare-earth fluoride nanomaterials.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115657"},"PeriodicalIF":3.0,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938348","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}
Pub Date : 2026-01-01DOI: 10.1016/j.comptc.2025.115656
Cesar Gabriel Vera de la Garza, Wilmer Esteban Vallejo Narvaez. Serguei Fomine
The hydrogen storage capacity of second-row transition-metal-decorated phosphorene nanoflakes (NFs) was investigated theoretically using the wB97M-D4/def2-TZVP(−f) level of theory. All second-row transition metals were found to form stable complexes with the phosphorene NFs. Among the series, NFs decorated with Mo, W, and Nb formed exergonic complexes with molecular hydrogen, with each metal atom capable of binding up to three H₂ molecules. The calculated Gibbs free binding energies ranged from −24.34 kcal/mol for the P–W–H2 complex to 22.94 kcal/mol for the P–Y–H2 complex. These complexes form without a significant activation energy barrier and involve partial dissociation of the HH bond. In specific cases, such as with W, Nb, and Mo, the binding mechanism involves hydride formation. Ab initio molecular dynamics simulations revealed a dynamic equilibrium between physisorption and chemisorption of H2 molecules. The theoretical highest hydrogen storage capacities, approximately 2.73–2.77 wt%, were exhibited by Mo, W, and Nb.
{"title":"Hydrogen storage in second-row transition metal-decorated phosphorene nanoflakes: A DFT investigation","authors":"Cesar Gabriel Vera de la Garza, Wilmer Esteban Vallejo Narvaez. Serguei Fomine","doi":"10.1016/j.comptc.2025.115656","DOIUrl":"10.1016/j.comptc.2025.115656","url":null,"abstract":"<div><div>The hydrogen storage capacity of second-row transition-metal-decorated phosphorene nanoflakes (NFs) was investigated theoretically using the wB97M-D4/def2-TZVP(−f) level of theory. All second-row transition metals were found to form stable complexes with the phosphorene NFs. Among the series, NFs decorated with Mo, W, and Nb formed exergonic complexes with molecular hydrogen, with each metal atom capable of binding up to three H₂ molecules. The calculated Gibbs free binding energies ranged from −24.34 kcal/mol for the P–W–H<sub>2</sub> complex to 22.94 kcal/mol for the P–Y–H<sub>2</sub> complex. These complexes form without a significant activation energy barrier and involve partial dissociation of the H<img>H bond. In specific cases, such as with W, Nb, and Mo, the binding mechanism involves hydride formation. Ab initio molecular dynamics simulations revealed a dynamic equilibrium between physisorption and chemisorption of H<sub>2</sub> molecules. The theoretical highest hydrogen storage capacities, approximately 2.73–2.77 wt%, were exhibited by Mo, W, and Nb.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115656"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880327","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}
Pub Date : 2025-12-31DOI: 10.1016/j.comptc.2025.115655
Yun Wang, Hai-Bei Li
This computational study systematically investigates a series of D-π-A-π-A organic dyes featuring triphenylamine as the donor, cyanoacrylic acid as the acceptor, and benzodiazole-based auxiliary acceptors (A1) with varied bridging moieties (CH2, NH, O, S, Se, and Te). Using density functional theory (DFT) and time-dependent DFT, we analyze their geometries, frontier orbitals, UV–Vis absorption, charge-transfer characteristics, and key photovoltaic parameters. All dyes exhibit favorable charge separation, suitable energy alignment with TiO₂ and electrolyte, high light-harvesting efficiency (>98 %), and sufficient open-circuit voltage (>0.7 V). Notably, the benzimidazole-based dye shows the smallest HOMO-LUMO gap and the most red-shifted absorption, highlighting its superior potential as a sensitizer. The work establishes a clear structure-property relationship and provides valuable insights for tailoring auxiliary acceptors for designing high-performance organic dyes.
{"title":"Photophysical properties of D-π-A-π-A organic dyes with benzodiazole-based auxiliary acceptors: A computational study","authors":"Yun Wang, Hai-Bei Li","doi":"10.1016/j.comptc.2025.115655","DOIUrl":"10.1016/j.comptc.2025.115655","url":null,"abstract":"<div><div>This computational study systematically investigates a series of D-π-A-π-A organic dyes featuring triphenylamine as the donor, cyanoacrylic acid as the acceptor, and benzodiazole-based auxiliary acceptors (A1) with varied bridging moieties (<img>CH<sub>2</sub><img>, <img>NH<img>, <img>O<img>, <img>S<img>, <img>Se<img>, and <img>Te<img>). Using density functional theory (DFT) and time-dependent DFT, we analyze their geometries, frontier orbitals, UV–Vis absorption, charge-transfer characteristics, and key photovoltaic parameters. All dyes exhibit favorable charge separation, suitable energy alignment with TiO₂ and electrolyte, high light-harvesting efficiency (>98 %), and sufficient open-circuit voltage (>0.7 V). Notably, the benzimidazole-based dye shows the smallest HOMO-LUMO gap and the most red-shifted absorption, highlighting its superior potential as a sensitizer. The work establishes a clear structure-property relationship and provides valuable insights for tailoring auxiliary acceptors for designing high-performance organic dyes.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115655"},"PeriodicalIF":3.0,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880328","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}
Self-consistent charge density functional tight-binding (SCC-DFTB) molecular dynamics simulations were employed to study the initial thermal decomposition mechanisms of 3,4-dinitro-1H-pyrazole (DNP) and 3,4-dinitrofurazanfuroxan (DNTF) eutectic mixture. Different from ordered and disordered models, the eutectic system exhibits unique decomposition behaviors. NO bond cleavage of DNTF predominates and increases with temperature, followed mainly by furoxan ring opening via CC breakage. NN bond rupture of DNP prevails, and pyrazole ring opening shifts to NN bong cleavage. Notably, DNTF decomposes more readily, while DNP reactivity lies intermediately. The eutetic system also exhibited significantly distinct decomposition product characteristics compared to both ordered and disordered models. The typical cleavage products of DNP and DNTF in the eutetic model were analyzed to revealed the thermal decomposition mechanism under different molecular stacking patterns. These results elucidate the synergy between molecular packing and temperature in governing decomposition mechanisms, advancing the understanding of sensitivity and thermal behavior in energetic materials.
{"title":"Temperature-dependent decomposition mechanism of a hot DNP/DNTF liquid eutectic model: Molecular-level insights from SCC-DFTB calculations","authors":"Yahong Chen , Zixuan Yang , Fangfang Hou , Shuangfei Zhu , Ruijun Gou , Shuhai Zhang","doi":"10.1016/j.comptc.2025.115650","DOIUrl":"10.1016/j.comptc.2025.115650","url":null,"abstract":"<div><div>Self-consistent charge density functional tight-binding (SCC-DFTB) molecular dynamics simulations were employed to study the initial thermal decomposition mechanisms of 3,4-dinitro-1H-pyrazole (DNP) and 3,4-dinitrofurazanfuroxan (DNTF) eutectic mixture. Different from ordered and disordered models, the eutectic system exhibits unique decomposition behaviors. N<img>O bond cleavage of DNTF predominates and increases with temperature, followed mainly by furoxan ring opening via C<img>C breakage. N<img>N bond rupture of DNP prevails, and pyrazole ring opening shifts to N<img>N bong cleavage. Notably, DNTF decomposes more readily, while DNP reactivity lies intermediately. The eutetic system also exhibited significantly distinct decomposition product characteristics compared to both ordered and disordered models. The typical cleavage products of DNP and DNTF in the eutetic model were analyzed to revealed the thermal decomposition mechanism under different molecular stacking patterns. These results elucidate the synergy between molecular packing and temperature in governing decomposition mechanisms, advancing the understanding of sensitivity and thermal behavior in energetic materials.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115650"},"PeriodicalIF":3.0,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880324","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}
Glyoxal (CHO)₂, an important oxidation product of volatile organic compounds (VOCs), acts as a key precursor to secondary organic aerosols (SOA), which influence atmospheric chemistry, cloud formation, and climate. Yet, its gas-phase reactions with small molecular acids and their catalytic roles in atmospheric nucleation remain unclear. Here, density functional theory (DFT) and high-level ab initio methods were used to explore the reaction pathways of glyoxal with sulfuric acid (H₂SO₄) and formic acid (HCOOH). Both acids exhibit strong catalytic effects, lowering activation barriers by 15.29 and 14.63 kcal·mol−1, respectively. Kinetic analyses show that the (HCO)₂ + H₂SO₄ reaction is the fastest, producing H(CHO)₂OSO₃H, which contributes to gas-phase degradation of glyoxal and sulfuric acid. The resulting binary complex may serve as a new nucleation precursor, providing insight into the early stages of atmospheric nucleation and SOA formation.
{"title":"New mechanistic pathways for the reactions of glyoxal with sulfuric acid and formic acid in atmosphere: The initial process of atmospheric nucleation","authors":"Jiyu Liu , Yongchao Zhao , Huafeng Wu , Meimei Yu , Zezhuan Jiang","doi":"10.1016/j.comptc.2025.115654","DOIUrl":"10.1016/j.comptc.2025.115654","url":null,"abstract":"<div><div>Glyoxal (CHO)₂, an important oxidation product of volatile organic compounds (VOCs), acts as a key precursor to secondary organic aerosols (SOA), which influence atmospheric chemistry, cloud formation, and climate. Yet, its gas-phase reactions with small molecular acids and their catalytic roles in atmospheric nucleation remain unclear. Here, density functional theory (DFT) and high-level ab initio methods were used to explore the reaction pathways of glyoxal with sulfuric acid (H₂SO₄) and formic acid (HCOOH). Both acids exhibit strong catalytic effects, lowering activation barriers by 15.29 and 14.63 kcal·mol<sup>−1</sup>, respectively. Kinetic analyses show that the (HCO)₂ + H₂SO₄ reaction is the fastest, producing H(CHO)₂OSO₃H, which contributes to gas-phase degradation of glyoxal and sulfuric acid. The resulting binary complex may serve as a new nucleation precursor, providing insight into the early stages of atmospheric nucleation and SOA formation.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115654"},"PeriodicalIF":3.0,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938346","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}
Pub Date : 2025-12-29DOI: 10.1016/j.comptc.2025.115648
Vandana Kumari Shukla, Nagaiyan Sekar
Sixteen donor-pi-acceptor (D-π-A) type sensitizers, which consist of pyrene as the donor unit coupled to various spacers and acceptor units, are investigated using density functional theory (DFT) and time dependent DFT (TD-DFT) techniques. The effects of substituting an ester group for carboxylic acid as acceptor on the system are investigated. The addition of ester causes the destabilization of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) of the sensitizers. In carboxylic acid acceptor-based sensitizers, the frontier molecular orbital (FMO) also illustrates an efficient intramolecular charge transfer (ICT) from the donor unit to the acceptor unit. Additionally, it is observed that ester acceptor-based sensitizers have higher computed open circuit voltage (Voc) values. According to the TD-DFT investigation, the acid acceptor-based sensitizers exhibit red-shifted vertical excitation. A positive solvatochromism is seen for all the sensitizers in TD-DFT calculations. The excited state dipole moment of acid acceptor-based sensitizer, calculated using Suppan's equation, is found to be more than the ester acceptor-based sensitizers. For the furan spacer based sensitizers with double bond between donor and spacer the following result is obtained- dipole moment moment in Debye (8.2: acid and 6.4: ester), HOMO-LUMO energy gap in eV (2.5: acid and 2.6: ester), electrophilicity index in eV (6.8: acid and 6.3: ester), hyperhardness in eV (1.7: acid and 1.8: ester) and absorption maxima in THF in nm (583: acid and 572: ester) in B3LYP functional.
{"title":"Comparison of the carboxylic acid and ester anchoring groups in pyrene-based sensitizers in DSSC: A computational investigation","authors":"Vandana Kumari Shukla, Nagaiyan Sekar","doi":"10.1016/j.comptc.2025.115648","DOIUrl":"10.1016/j.comptc.2025.115648","url":null,"abstract":"<div><div>Sixteen donor-pi-acceptor (D-π-A) type sensitizers, which consist of pyrene as the donor unit coupled to various spacers and acceptor units, are investigated using density functional theory (DFT) and time dependent DFT (TD-DFT) techniques. The effects of substituting an ester group for carboxylic acid as acceptor on the system are investigated. The addition of ester causes the destabilization of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) of the sensitizers. In carboxylic acid acceptor-based sensitizers, the frontier molecular orbital (FMO) also illustrates an efficient intramolecular charge transfer (ICT) from the donor unit to the acceptor unit. Additionally, it is observed that ester acceptor-based sensitizers have higher computed open circuit voltage (Voc) values. According to the TD-DFT investigation, the acid acceptor-based sensitizers exhibit red-shifted vertical excitation. A positive solvatochromism is seen for all the sensitizers in TD-DFT calculations. The excited state dipole moment of acid acceptor-based sensitizer, calculated using Suppan's equation, is found to be more than the ester acceptor-based sensitizers. For the furan spacer based sensitizers with double bond between donor and spacer the following result is obtained- dipole moment moment in Debye (8.2: acid and 6.4: ester), HOMO-LUMO energy gap in eV (2.5: acid and 2.6: ester), electrophilicity index in eV (6.8: acid and 6.3: ester), hyperhardness in eV (1.7: acid and 1.8: ester) and absorption maxima in THF in nm (583: acid and 572: ester) in B3LYP functional.</div></div>","PeriodicalId":284,"journal":{"name":"Computational and Theoretical Chemistry","volume":"1256 ","pages":"Article 115648"},"PeriodicalIF":3.0,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938347","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}
Pub Date : 2025-12-29DOI: 10.1016/j.comptc.2025.115643
Ananta Panigrahi, Prabhat K. Sahu
This study presents a series of novel D–π–A organic dyes (1 A–4H) designed for dye-sensitized solar cells (DSSCs) using DFT and TD-DFT at 6–31 + G* level. Incorporating donor groups (amino, dimethylamine, methoxy, diphenylamine), fused thiophene and Thiazolo[5,4-d] thiazole π-spacers, and acceptors like –NO₂, –CN, and cyanoacrylic acid (CAA), the dyes are analyzed for optoelectronic performance. CAA-based dyes show enhanced intramolecular charge transfer, red-shifted absorption, and higher molar extinction coefficients. Dyes 1F, 1H, 4F, and 4H exhibit broader absorption bands, higher light-harvesting efficiency (up to 96.17 %), lower chemical hardness, and stronger electron injection driving force. Their large vertical dipole moments and increased conduction band electron population support superior photovoltaic performance. The computed results also support with favourable ionization energy, electron affinity, and reorganization energies. These findings highlight 1F, 1H, 4F, and 4H dyes for high-efficiency DSSC applications, warranting further experimental validation.
本研究利用DFT和TD-DFT在6-31 + G*水平上设计了一系列用于染料敏化太阳能电池（DSSCs）的新型D -π-A有机染料（1 a - 4h）。结合给基（氨基、二甲胺、甲氧基、二苯胺）、融合噻吩和噻唑[5,4-d]噻唑π-间隔基团以及受体（-NO₂、-CN、氰丙烯酸（CAA）），对染料进行了光电性能分析。caa基染料表现出增强的分子内电荷转移、红移吸收和更高的摩尔消光系数。染料1F、1H、4F和4H具有较宽的吸收带、较高的光收集效率（可达96.17%）、较低的化学硬度和较强的电子注入驱动力。它们大的垂直偶极矩和增加的导带电子居群支持优越的光伏性能。计算结果也支持有利的电离能、电子亲和能和重组能。这些发现突出了1F、1H、4F和4H染料在高效DSSC中的应用，需要进一步的实验验证。
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