Physical Chemistry Chemical Physics最新文献

{"title":"Which molecules for photoinduced symmetry-breaking charge separation? A thermodynamic perspective.","authors":"Johannes Wega, Eric Vauthey","doi":"10.1039/d6cp03256g","DOIUrl":"10.1039/d6cp03256g","url":null,"abstract":"<p><p>Photoinduced symmetry-breaking charge separation (SB-CS) is an electron-transfer between two identical molecules (M) following photoexcitation of one of them (M* + M → M˙⁺ + M˙^-). Compared to conventional photoinduced electron transfer with distinct donor and acceptor moieties, SB-CS offers several advantages for light-driven applications such as organic photovoltaics and photoredox catalysis. Despite its renewed interest, the molecular properties governing SB-CS remain poorly understood. Herein, we systematically evaluate the free energy for SB-CS (Δ<i>G</i>0SB-CS) for nearly 40 polycyclic aromatic hydrocarbons using experimental gas-phase properties combined with quantum-chemically computed solvation energies. We identify several promising aromatic frameworks for rational SB-CS chromophore design (at least from a thermodynamic perspective) and elucidate the role of molecular structure, redox properties, solvation energy and excited-state character. Most notably, we find a correlation between the singlet-triplet energy gap and Δ<i>G</i>0SB-CS, which we attribute to differences in the exchange integrals of the different chromophores. This relationship explains, for example, why anthracene exhibits a large thermodynamic driving force for SB-CS, whereas azulene does not, despite their essentially identical redox and solvation properties.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":"24506-24519"},"PeriodicalIF":3.0,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035646","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":"Ab Initio Diabatic Potential Energy Matrix for the Lowest-lying Singlet States of HCN Responsible for Collisional Excitation/Quenching of CN(X2Σ+/A2Π) with H","authors":"Yang Liu,Hua Guo","doi":"10.1039/d6cp02777f","DOIUrl":"https://doi.org/10.1039/d6cp02777f","url":null,"abstract":"In hyperthermal chemistry, eElectronically excited cyano radicals (CN) are considered as a key radiative source in hyperthermal chemistry in the shock boundary layer in front of supersonic (re)entry vehicles. To correctly model the radiative heating in such extreme environments, it is necessary to understand collisional excitation and quenching rates. Although quenching of CN(A2Π) to CN(X2Σ+) with various collision partners has been investigated experimentally, a quantitative understanding of the nonadiabatic transitions in such electronically inelastic scattering has not been achieved. In this work, a full-dimensional diabatic potential energy matrix (DPEM) for the three lowest-lying singlet A′ states of HCN, namely the 1 1 A′, 2 1 A′, and 3 1 A′ states, are developed based on multi-reference configuration interaction calculations. The DPEM provides valuable insights into the quenching/excitation of CN(X2Σ+/A2Π) via collisions with H in the singlet manifold.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"19 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149173147","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 analysis of the metal-free H₂ dissociation mechanism by semiquinone radicals in mitochondrial Complex I and III","authors":"Toru Ishibashi,Enjuro Harunari","doi":"10.1039/d6cp02775j","DOIUrl":"https://doi.org/10.1039/d6cp02775j","url":null,"abstract":"Although ameliorative effects of molecular hydrogen (H₂) have been reported in a wide range of pathological conditions, it remained unresolved what molecular mechanism activates H₂ in animal cells, which lack the metal hydrogenases that dissociate the nonpolar, among-the-strongest-known H–H bond. Using first-principles calculations (B3LYP-D3BJ/def2-SVP/CPCM geometries, ωB97M-V/def2-TZVPP energies) on active-site clusters of the Q-chamber of mitochondrial Complex I (PDB 7QSK) and the Qo site of Complex III (PDB 1PP9), this study examined whether semiquinone could directly dissociate H₂ in the low-dielectric environment buried within the enzyme, and what changes when a conserved residue is added as a second hydrogen atom acceptor. At both sites the anionic semiquinone Q•⁻ had no reaction pathway for cleaving H–H, and only the neutral QH•, protonated by nearby residues, opened a homolytic hydrogen atom transfer (HAT) pathway with a well-defined transition state. The spin density on the transferring hydrogen, rising continuously to +0.99 for free H•, confirms a true homolytic HAT. For HAT with a single hydrogen atom acceptor the reaction energy of QH• + H₂ → QH₂ + H• is +28.3 kcal/mol, and the barrier cannot fall below it. In the Q-chamber the conserved Tyr108 can act as a second acceptor, and with H₂ held between QH• and TyrO• the barrier falls to +27.0 kcal/mol. This reactive QH• arises only under hyper-reductive pressure, where quinone-pool overreduction and high membrane potential coincide. Because H₂ has among the strongest σ bonds, the barrier is high and sharp, and quantum tunnelling contributes substantially to crossing it at body temperature. The crossover temperatures are 293.9 K for Complex I and 264.7 K for Complex III. In solution, where we previously observed a Marcus inverted region, what tunnels is the electron, along a coordinate distinct from the hydrogen nucleus analysed here. The predicted primary isotope effect (kH/kD ≈ 4) could be tested with D₂ as a tracer. This shifts the mechanistic account of H₂ medicine from classical antioxidant scavenging to redox regulation as a quantum-tunnelling-assisted conditional hydrogenase activity conditioned by reductive pressure, and positions it as a field of quantum biology.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"158 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149173150","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":"The reaction between W(N) and N: the importance of the adsorption barrier","authors":"Kai-Wen Liu,Bin Yang,Ke-Wei Ding,Xi-Ling Xu,Hong-Guang Xu,Wei-Jun Zheng","doi":"10.1039/d6cp03221d","DOIUrl":"https://doi.org/10.1039/d6cp03221d","url":null,"abstract":"Theoretical calculations indicate that the reaction of W(N2)5− with N2 to form octahedral W(N2)6− is exothermic, which suggests that W(N2)6− is more stable than W(N2)5−. However, our experiments show that the ion signal of W(N2)6− is much weaker than that of W(N2)5−. A detailed theoretical study reveals that there is a weak interaction barrier for adsorption at a W–N distance of about 2.8 Å along the W(N2)5− + N2 reaction pathway, whereas the corresponding neutral reaction, W(N2)5 + N2, is barrierless. The weak interaction barrier is primarily due to repulsion between the electrons in the frontier molecular orbitals of W(N2)5− and N2 at long range. The studies therefore confirm that the formation of octahedral W(N2)6− is hindered by kinetics rather than by thermodynamics.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"48 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149173166","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":"Expanding the polarizing agent toolbox for liquid-state dynamic nuclear polarization: stability and performance at 14.1 T.","authors":"Kiera Powers, Daphne Broerman, John Cerritelli, Sanyog Kumari, Snorri Th Sigurdsson, Linda H Doerrer, Tomas Orlando","doi":"10.1039/d6cp03024f","DOIUrl":"https://doi.org/10.1039/d6cp03024f","url":null,"abstract":"<p><p>Dynamic nuclear polarization (DNP) in liquids is emerging as a potential technique to increase the NMR signal of routine NMR spectroscopy at high magnetic fields. Monoradicals are utilized as polarizing agents and microwave irradiation is used to transfer the high electron spin polarization to nuclei on nearby molecules. Recently, narrow-line radicals have gained significant interest as polarizing agents because they can efficiently polarize a broad set of nuclei (¹H, ¹³C, ¹⁹F, ³¹P) in various systems, such as neat liquids, viscous liquids, and heterogeneous media. However, these radicals can be unstable in solutions, which can make data reproducibility difficult. Here, we studied the persistence of narrow-line radicals in organic solvents typically used as matrices in liquid DNP. We observed that the persistence of monoradicals varies significantly depending on the monoradical, the solvent, and the storage condition of the sample. Our results aim to serve as a guideline for sample preparation and data reproducibility. Furthermore, we expand the viable class of polarizing agents by introducing two radicals that are new in the context of DNP in liquids driven by the Overhauser effect at high magnetic fields; verdazyl and tris(pentafluorophenyl)methyl (PF-trityl). Our ¹⁹F-DNP experiments at 14.1 T show that PF-trityl can polarize aromatic and aliphatic fluorinated molecules equally well, a feature that has not yet been reported and that may be ascribed to the fluorination of the radical itself.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177920","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":"Anion basicity orders hydration structure and dynamics in imidazolium ionic liquid-water mixtures: a systematic NMR shift and linewidth study.","authors":"Shilpa Ramesh, Johanna C van der Bok, Giuditta Perversi, Laura J B M Kollau","doi":"10.1039/d6cp03080g","DOIUrl":"https://doi.org/10.1039/d6cp03080g","url":null,"abstract":"<p><p>Ionic liquid-water mixtures are widely used in electrochemical, separation, and process applications. However, how anion identity shapes the hydration response across the full composition range has not been systematically quantified. Here we report a systematic study of three 1-ethyl-3-methylimidazolium ([EMIM]⁺) ionic liquids paired with anions of distinct hydrogen-bond basicity: chloride (Cl^-), tetrafluoroborate (BF₄^-), and diethyl phosphate (DEP^-). Viscosity, conductivity, ¹H, ¹⁹F, and ³¹P NMR chemical shifts and linewidths were measured across the accessible composition range. Across the three systems studied here, anion basicity orders the measured observables consistently, from the neat-liquid imidazolium C2-H (H2) chemical shift and linewidth to the position of the water ¹H shift minimum, following the sequence DEP^- > Cl^- > BF₄^-. In [EMIM][Cl] and [EMIM][DEP], the water shift and linewidth minima occur at similar compositions, consistent with coupled structural and dynamic changes; in [EMIM][BF₄], the water shift plateaus while the linewidth minimum occurs at a distinctly higher water content, a linewidth-based observation consistent with the structural crossover independently reported by optical Kerr effect and neutron scattering studies in this composition range. [EMIM][DEP] additionally shows a V-shaped ³¹P response consistent with multi-stage phosphate hydration. These results identify anion basicity as a practical first-order descriptor for IL-water behaviour in the systems studied here, with NMR linewidth as a necessary complement to chemical shift.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177820","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":"Investigation of a possible atmospheric degradation product from HFO-1336mz (CF₃CHCHCF₃) using photolysis of CF₃CH(OH)CH₂Br.","authors":"Mads Peter Sulbaek Andersen, Ole John Nielsen","doi":"10.1039/d6cp03074b","DOIUrl":"https://doi.org/10.1039/d6cp03074b","url":null,"abstract":"<p><p>HFO-1336mz (1,1,1,4,4,4-hexafluoro-2-butene, CF₃CHCHCF₃) is used as a heat transfer fluid, blowing agent and high-temperature heat pump fluid. It is important to understand the fate of HFO-1336mz in the atmosphere. 3,3,3-Trifluoro-2-hydroxypropanal, CF₃CH(OH)CHO has been speculated to be an intermediate degradation product from HFO-1336mz, which will be further photolyzed in the atmosphere. In this chamber study, 254 nm photolysis of CF₃CH(OH)CH₂Br was used to produce CF₃CH(OH)CHO and FTIR spectroscopy was used for detection of the photolysis products. In the absence of NO, the photolysis of CF₃CH(OH)CH₂Br produces CF₃CH(OH)CHO in a yield indistinguishable from unity. Subsequent photolysis of this hydroxyaldehyde gives predominantly COF₂ with smaller yields of CF₃CHO and CF₃CH₂OH. Following the initial photolytic cleavage of the C-Br bond in CF₃CH(OH)CH₂Br, a hot alkoxy reaction was observed, in addition to products consistent with a H-atom roaming pathway. The photolysis rate was measured relative to that of CH₃CHO, and a quantum yield indistinguishable from unity was established (<i>Φ</i>_254 nm = 0.96 ± 0.11).</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149177923","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":"Molecular mechanisms of typical chelating agents influencing the early hydration of C₃S: a combined MD and DFT study.","authors":"Yunqi Liu, Fengxiao Zhu, Yanchen Ren, Dongshuai Hou, Pan Wang, Muhan Wang, Xinpeng Wang, Jing Guan, Jian Xiao, Tao Li, Zhibin Zheng, Yue Zhang","doi":"10.1039/d6cp03378d","DOIUrl":"https://doi.org/10.1039/d6cp03378d","url":null,"abstract":"<p><p>Organic chelating agents are widely used to regulate cement hydration, yet the molecular relationship between ligand structure, interfacial adsorption, and mineral dissolution remains unclear. To overcome the limitations of single-scale approaches, this study employs a comprehensive synergistic framework combining density functional theory (DFT), well-tempered metadynamics, and unbiased molecular dynamics (MD). This framework investigates four typical chelating agents-acetic acid (AA), citric acid (CA), EDTA, and sodium gluconate (SG)-specifically selected for their distinct and representative arrangements of carboxylate, hydroxyl, and amine groups, evaluating their effects on C₃S dissolution. This multiscale strategy successfully bridges precise electronic structures with dynamic hydration kinetics. Static DFT calculations show that multidentate ligands establish strong interactions with surface Ca sites <i>via</i> Na⁺-mediated ternary anchoring, whereas flexible ligands like SG exhibit weaker static adsorption. Metadynamics further reveals distinct retardation mechanisms by mapping the free-energy landscape: CA and EDTA operate <i>via</i> an inductive-trapping mechanism, stabilizing departing Ca in high-coordination free-energy minima to increase the barrier for further detachment, whereas SG elevates the dissolution barrier primarily through a steric-hindrance mechanism. Unbiased MD simulations demonstrate that chelator adsorption delays the complete surface decoordination of Ca, reorganizes the local water structure, and competitively restricts interfacial ion transport. Ultimately, the intrinsic capability to inhibit Ca release follows the sequence of EDTA > CA > SG > AA. These results link molecular coordination, interfacial adsorption, and dissolution energetics, providing a robust mechanistic basis for understanding chelator-induced retardation of C₃S hydration.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149178091","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":"Tip–sample distance dependence of local work function in Kelvin probe force microscopy on Pb/Si(111) islands","authors":"Daniel Rothhardt,Thomas Späth,Paul Philip Schmidt,Ralf Metzler,Regina Hoffmann-Vogel","doi":"10.1039/d6cp02307j","DOIUrl":"https://doi.org/10.1039/d6cp02307j","url":null,"abstract":"To gain a better understanding of the Kelvin probe force microscopy (KPFM) method, it is important to obtain a quantitative understanding of the measured contact potential dierence (CPD) values as a function of tip-sample distance. This will allow a more complete quantitative understanding of the electronic properties and the forces acting on the tip. Here, we chose Pb islands on the Si(111) 7 × 7 surface, metallic islands on a semiconducting surface. Using a Scanning Force Microscope in frequency modulation mode we perform point bias-approach measurements at 120 K on Pb islands. We investigate how the CPD changes as a function of tip-sample distance and how the electrostatic force changes as a function of the applied bias between tip and sample. The measured distance dependence of the CPD not only allows to connect between the point-of-view of atomic resolution KPFM and of averaging effects of the body of the tip but also allows to investigate the shape of charged objects on the surface.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"21 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149173156","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":"Effect of Tetrahydrofuran on the Optoelectronic Properties of PEDOT:PSS","authors":"Yifan Zhang,Sumei Wu,Menhong Qian,Yao Liang,Zhihua Zhang,Hui Liu,Xiang Liu","doi":"10.1039/d6cp01918h","DOIUrl":"https://doi.org/10.1039/d6cp01918h","url":null,"abstract":"Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is an important conductive polymer. In its pristine form, however, its electrical conductivity is relatively low, which still cannot meet the requirements of practical applications. Solvent treatment is commonly used to improve its optoelectronic properties. Currently, while numerous experimental interpretations have been put forward regarding the mechanism driving the enhancement of optoelectronic properties induced by tetrahydrofuran (THF), the theoretical insights derived from simulations and modeling remain inadequate. In this work, spray coating was used to fabricate different PEDOT:PSS films, which contains pristine film, post-infiltration treatment film, post-drop-casting treatment film and solvent-treated film. We conducted simulations to replicate the intricate real world morphology of PEDOT:PSS, molecular dynamics (MD) simulation and density functional theory (DFT) simulation were employed to explain the modification mechanism of THF solvent-treated PEDOT:PSS thin films. We demonstrate that a certain degree of phase separation occurs between conductive PEDOT and insulating PSS after solvent treatment. PSS with high crystallinity dissolves extensively in polar organic solvents during dilution, leading to the aggregation of PEDOT, as well as increased interchain contact forces and charge transfer. Excess PSS is removed through the nanoscale phase separation induced by the addition of polar organic solvents.Enhance the overall optoelectronic performance.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"19 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149173157","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}