The interface between a weakly adsorbed, solvated cation and a metal electrode is investigated by density functional theory using a hybrid implicit-explicit solvation model. The cations remain charged upon adsorption, the counter-charge resides on the metal surface. There is no diffuse double-layer in this system; experimentally this corresponds to adsorption from a low concentration of cations. The change Δϕ in electrode potential upon adsorption is determined from the change in the electrostatic potential at large distances from the electrode. The phenomenon of partial charge transfer leads to two separate operational definitions for the charge on the ions: the formal charge ze0, where z is the valency, and the partial charge remaining after adsorption, which we quantify with the Bader charge. The measurable integral capacitance is determined by ze0, and for all systems investigated it lies in a range which compares well with experimental data. The divalent ions Ca2+ and Mg2+ show a substantial partial charge transfer, which enhances the capacitance. In contrast, alkali ions K+ and Na+ keep their unit charge. Since there is no diffuse layer, the electrosorption valency equals the negative of the partial charge transfer. Interpreting our results within a simple parallel plate capacitor model allows us to calculate an effective dielectric constant, governed mainly by contributions from the polarizabilities of the metal surface and of the water molecules. Thus, our model provides important insights into the structure of the compact double-layer and its concomitant interactions.
{"title":"The Effect of Weakly Adsorbed Cations on the Helmholtz Capacitance of Metal–Water Interfaces","authors":"Fabiola Domínguez-Flores,Axel Groß,Wolfgang Schmickler","doi":"10.1021/acs.jpcc.5c08002","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c08002","url":null,"abstract":"The interface between a weakly adsorbed, solvated cation and a metal electrode is investigated by density functional theory using a hybrid implicit-explicit solvation model. The cations remain charged upon adsorption, the counter-charge resides on the metal surface. There is no diffuse double-layer in this system; experimentally this corresponds to adsorption from a low concentration of cations. The change Δϕ in electrode potential upon adsorption is determined from the change in the electrostatic potential at large distances from the electrode. The phenomenon of partial charge transfer leads to two separate operational definitions for the charge on the ions: the formal charge ze0, where z is the valency, and the partial charge remaining after adsorption, which we quantify with the Bader charge. The measurable integral capacitance is determined by ze0, and for all systems investigated it lies in a range which compares well with experimental data. The divalent ions Ca2+ and Mg2+ show a substantial partial charge transfer, which enhances the capacitance. In contrast, alkali ions K+ and Na+ keep their unit charge. Since there is no diffuse layer, the electrosorption valency equals the negative of the partial charge transfer. Interpreting our results within a simple parallel plate capacitor model allows us to calculate an effective dielectric constant, governed mainly by contributions from the polarizabilities of the metal surface and of the water molecules. Thus, our model provides important insights into the structure of the compact double-layer and its concomitant interactions.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"295 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138802","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 : 2026-02-09DOI: 10.1021/acs.jpcc.5c08525
M. P. Lijina,Alfy Benny,Suvarna Sujilkumar,Mahesh Hariharan
Atypical photophysical behaviors of organic chromophores, tailored by exciton interactions, are of immense importance owing to the implications in fabricating photofunctional materials. Kasha’s exciton theory offers a comprehensive framework for understanding molecular arrays, predicting unique exciton splitting in dimer and trimer systems, and their resulting optoelectronic properties. Herein, we report an investigation of an unexplored molecular triangle in a crystalline pentacene derivative shaped by noncovalent interactions as well as an extension to linear acene trimer models. The energetic alignment of excited states was portrayed using TD-DFT, which suggests a partially split triple degeneracy according to the alignment of transition dipoles, in agreement with the molecular exciton model. The crystalline pentacene triangle exhibits weak excitonic coupling due to significant interchromophoric separation, which is reflected in the optical properties. The study of the triangular architecture offers valuable insights into exciton theory in emerging photonic materials.
{"title":"Near-Triangular Imprint in Crystalline Pentacene: A Search for Kasha’s Exciton Trimer in a Noncovalent Chromophoric Assembly","authors":"M. P. Lijina,Alfy Benny,Suvarna Sujilkumar,Mahesh Hariharan","doi":"10.1021/acs.jpcc.5c08525","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c08525","url":null,"abstract":"Atypical photophysical behaviors of organic chromophores, tailored by exciton interactions, are of immense importance owing to the implications in fabricating photofunctional materials. Kasha’s exciton theory offers a comprehensive framework for understanding molecular arrays, predicting unique exciton splitting in dimer and trimer systems, and their resulting optoelectronic properties. Herein, we report an investigation of an unexplored molecular triangle in a crystalline pentacene derivative shaped by noncovalent interactions as well as an extension to linear acene trimer models. The energetic alignment of excited states was portrayed using TD-DFT, which suggests a partially split triple degeneracy according to the alignment of transition dipoles, in agreement with the molecular exciton model. The crystalline pentacene triangle exhibits weak excitonic coupling due to significant interchromophoric separation, which is reflected in the optical properties. The study of the triangular architecture offers valuable insights into exciton theory in emerging photonic materials.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"12 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138798","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 : 2026-02-09DOI: 10.1021/acs.jpcc.5c07618
Juan D. Jiménez,Hong Zhang,Maila Danielis,Sara Colussi,Ping Liu,Sanjaya D. Senanayake
Herein, we present a systematic comparison between Pd carbonyl (Pd-CO) species, specifically over Pd/CeO2 based catalysts, observed during isothermal adsorption and in several prototypical catalytic reactions to identify and understand CO adsorption on palladium–ceria based catalysts. Pd-CO is observed via DRIFTS to probe the gas–solid conditions, while ATR-IR is used to probe the affinity of Pd-CO under more complex solvated gas–solid–liquid conditions to discern the influence of the microenvironments for carbonyl adsorption. We explore the presence of Pd-CO under several reactive environments, including CO adsorption, CO2 + H2, CO + H2, CH4 + CO2 and CO under gas–solid–liquid media, highlighting reactions with notable Pd-CO formation. The differences between palladium carbonyls and carbonate species show that carbonyl species are much more affected via a shifting of the peak position than carbonates, which remain static irrespective of the immediate chemical environment. By following the rate of CO accumulation via K–M mode DRIFTS, we observe migration from linear, 2095 cm–1, to bridge site, 1978 cm–1, as a function of time under a static CO atmosphere. With the use of DFT, we discerned changes in Pd-carbonyl stretches due to both coverage effects of CO under simulated reaction conditions and temperature effects. Regardless of whether CO is formed as an intermediate or a reactant, the competitive adsorption of *H and *CO affects the binding strength of *CO at all temperatures, with low temperature favoring atop binding and high temperature favoring the more stable FCC Pd-CO site.
{"title":"Identification of Carbonyl Species on Palladium Supported on Ceria in Complex Microenvironments","authors":"Juan D. Jiménez,Hong Zhang,Maila Danielis,Sara Colussi,Ping Liu,Sanjaya D. Senanayake","doi":"10.1021/acs.jpcc.5c07618","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c07618","url":null,"abstract":"Herein, we present a systematic comparison between Pd carbonyl (Pd-CO) species, specifically over Pd/CeO2 based catalysts, observed during isothermal adsorption and in several prototypical catalytic reactions to identify and understand CO adsorption on palladium–ceria based catalysts. Pd-CO is observed via DRIFTS to probe the gas–solid conditions, while ATR-IR is used to probe the affinity of Pd-CO under more complex solvated gas–solid–liquid conditions to discern the influence of the microenvironments for carbonyl adsorption. We explore the presence of Pd-CO under several reactive environments, including CO adsorption, CO2 + H2, CO + H2, CH4 + CO2 and CO under gas–solid–liquid media, highlighting reactions with notable Pd-CO formation. The differences between palladium carbonyls and carbonate species show that carbonyl species are much more affected via a shifting of the peak position than carbonates, which remain static irrespective of the immediate chemical environment. By following the rate of CO accumulation via K–M mode DRIFTS, we observe migration from linear, 2095 cm–1, to bridge site, 1978 cm–1, as a function of time under a static CO atmosphere. With the use of DFT, we discerned changes in Pd-carbonyl stretches due to both coverage effects of CO under simulated reaction conditions and temperature effects. Regardless of whether CO is formed as an intermediate or a reactant, the competitive adsorption of *H and *CO affects the binding strength of *CO at all temperatures, with low temperature favoring atop binding and high temperature favoring the more stable FCC Pd-CO site.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"70 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138800","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}
To address the spectral deficiencies in the red region of commercial white LEDs, developing red-emitting phosphors with reduced dependence on rare-earth elements with limited availability is crucial for spectral compensation. Herein, microstructures and optical characteristics of Mn4+-activated Mg2GeO4 phosphors are presented. While the phosphor exhibits a single orthorhombic phase, its cryogenic micro-Raman and photoluminescence (PL) spectra comprises 19 peaks and three groups of vibronic emissions with wealthy fine structures, respectively. Following the split zero-phonon lines, nine pairs of vibronic lines with an energy separation of 3.5 meV are identified. Furthermore, the overall line shape of the three groups of phonon sidebands can be reproduced by the fully symmetric electron–phonon coupling model, enabling determination of the total density of phonon states. The study sheds light on complicated luminescence fine structures in Mn4+-activated oxide phosphors, offering valuable insights into the design of red-emitting phosphors.
{"title":"Optical Properties of Mg2GeO4:Mn4+ Phosphors: From Fine Structures of Vibronic Transitions to the Density of Phonon States","authors":"Hongyi Zhu,Yitong Wang,Wanggui Ye,Tianlong Ruan,Fei Tang,Jiqiang Ning,Shijie Xu","doi":"10.1021/acs.jpcc.5c07885","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c07885","url":null,"abstract":"To address the spectral deficiencies in the red region of commercial white LEDs, developing red-emitting phosphors with reduced dependence on rare-earth elements with limited availability is crucial for spectral compensation. Herein, microstructures and optical characteristics of Mn4+-activated Mg2GeO4 phosphors are presented. While the phosphor exhibits a single orthorhombic phase, its cryogenic micro-Raman and photoluminescence (PL) spectra comprises 19 peaks and three groups of vibronic emissions with wealthy fine structures, respectively. Following the split zero-phonon lines, nine pairs of vibronic lines with an energy separation of 3.5 meV are identified. Furthermore, the overall line shape of the three groups of phonon sidebands can be reproduced by the fully symmetric electron–phonon coupling model, enabling determination of the total density of phonon states. The study sheds light on complicated luminescence fine structures in Mn4+-activated oxide phosphors, offering valuable insights into the design of red-emitting phosphors.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"295 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138801","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 : 2026-02-09DOI: 10.1021/acs.jpcc.5c06383
Weihua Wu,Robbert W. E. van de Kruijs,Dirk J. Gravesteijn,Z. Silvester Houweling,Giorgio Colombi,Alexey Y. Kovalgin
In this work, we develop and validate a spectroscopic ellipsometry (SE) approach to first monitor the performance of a thin-film palladium/hafnium (Pd/Hf) hydrogen detection sensor suitable for applications up to a temperature of 450 °C and second to quantify the hydrogen permeation through thin capping layers. A 2.5 nm aluminum oxide (Al2O3) thin film is tested as a potential protective hydrogen barrier under hydrogen radical (H*) flux conditions found in extreme ultraviolet lithography scanners. To this end, the interaction between molecular and atomic hydrogen and a Pd/Hf stack was studied at temperatures from 120 to 670 °C. Optical and structural changes during hydrogen exposures were investigated using in situ SE and ex situ X-ray diffraction. The stack is confirmed to remain stable in the respective metallic phases during vacuum annealing up to 450 °C without forming any crystalline HfO2 by reaction with trace oxidative species. Upon molecular H2 exposure, the formation of hafnium hydride (HfHx) can be observed for temperatures up to 350 °C, while Hf oxidation occurs at higher temperatures. Upon exposure to H*, HfHx formation is observed for temperatures up to 450 °C, again followed by oxidation at higher temperatures. Capping the stack with a 2.5 nm Al2O3 layer fabricated by atomic layer deposition led to a retardation of 70 times for hydrogenation upon H* exposure at 450 °C accompanied by little oxidation. An analytical SE model was developed for analyzing the H-content incorporated into this stack through the Al2O3 capping layer, showing a decent match with that from absolute quantification by elastic recoil detection analysis.
{"title":"Sensing of Hydrogen Diffusion through Protective Caps: An Ellipsometric Approach to Estimate Hydrogen Content in Pd/Hf Stacks with an Al2O3 Cap","authors":"Weihua Wu,Robbert W. E. van de Kruijs,Dirk J. Gravesteijn,Z. Silvester Houweling,Giorgio Colombi,Alexey Y. Kovalgin","doi":"10.1021/acs.jpcc.5c06383","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c06383","url":null,"abstract":"In this work, we develop and validate a spectroscopic ellipsometry (SE) approach to first monitor the performance of a thin-film palladium/hafnium (Pd/Hf) hydrogen detection sensor suitable for applications up to a temperature of 450 °C and second to quantify the hydrogen permeation through thin capping layers. A 2.5 nm aluminum oxide (Al2O3) thin film is tested as a potential protective hydrogen barrier under hydrogen radical (H*) flux conditions found in extreme ultraviolet lithography scanners. To this end, the interaction between molecular and atomic hydrogen and a Pd/Hf stack was studied at temperatures from 120 to 670 °C. Optical and structural changes during hydrogen exposures were investigated using in situ SE and ex situ X-ray diffraction. The stack is confirmed to remain stable in the respective metallic phases during vacuum annealing up to 450 °C without forming any crystalline HfO2 by reaction with trace oxidative species. Upon molecular H2 exposure, the formation of hafnium hydride (HfHx) can be observed for temperatures up to 350 °C, while Hf oxidation occurs at higher temperatures. Upon exposure to H*, HfHx formation is observed for temperatures up to 450 °C, again followed by oxidation at higher temperatures. Capping the stack with a 2.5 nm Al2O3 layer fabricated by atomic layer deposition led to a retardation of 70 times for hydrogenation upon H* exposure at 450 °C accompanied by little oxidation. An analytical SE model was developed for analyzing the H-content incorporated into this stack through the Al2O3 capping layer, showing a decent match with that from absolute quantification by elastic recoil detection analysis.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"241 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138799","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 : 2026-02-08DOI: 10.1021/acs.jpcc.5c05791
Florentino López-Urías,Francisco Sánchez-Ochoa
We investigated the honeycomb lattice using a two-orbital (α and β) Hubbard model and many-body exact calculations. The spin gap (Δs), charge gap (Δc), intrasite (γiiαβ=⟨S→iα·S→iβ⟩), intersite (γijαβ=⟨S→iα·S→jβ⟩), spin–spin correlations, and orbital magnetic moments μiα are analyzed for different band-filling (n), which denotes the number of electrons per site. Special attention was set in one-quarter-filled (n = 1) and half-filled (n = 2) bands. The results are presented by varying Coulomb repulsion (U), Hund’s coupling (JH), external magnetic field (B), and orbital energy splitting (Δϵ). For the one-quarter-filled band, an intrasite magnetic disorder (γiiαβ≈0) begins to form for large values of U/t, which is interpreted as a possible signature of a resonating valence bond state. Full orbital polarization (γiiαβ=0.25) with intersite antiferromagnetic (AFM) order (γijαβ=−0.25) was observed in the half-filled band for U/t ≫ 1, indicating that the two-orbital Hubbard model can be mapped to an AFM Heisenberg model with S = 1. The increase of JH is conductive to insulating and metallic phases for half- and one-quarter-filled bands, respectively. For a fractional n, the honeycomb lattice can exhibit spin-glass-like behavior, predominating as a disordered magnetic system characterized by random values of γijαβ. The magnetic field induced a reduction in Δc, which became zero at the critical external magnetic field. Twisted bilayer graphene (TBG) exhibits approximately flat electronic bands at magic angles and interesting correlated phenomena, such as unconventional superconductivity and correlated insulating states around n = 1 and n = 2, respectively. The dominance of electron–electron interactions in TBG makes the Hubbard model, in various versions (extended or multi-orbital), offer a practical, structure-scale account for investigating many-body effects in large moiré unit cells, where first-principles density-functional theory calculations are computationally challenging.
{"title":"Electron Correlations Study toward Understanding Twisted Bilayer Graphene: Two-Orbital Hubbard Model and Exact Numerical Calculations","authors":"Florentino López-Urías,Francisco Sánchez-Ochoa","doi":"10.1021/acs.jpcc.5c05791","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c05791","url":null,"abstract":"We investigated the honeycomb lattice using a two-orbital (α and β) Hubbard model and many-body exact calculations. The spin gap (Δs), charge gap (Δc), intrasite (γiiαβ=⟨S→iα·S→iβ⟩), intersite (γijαβ=⟨S→iα·S→jβ⟩), spin–spin correlations, and orbital magnetic moments μiα are analyzed for different band-filling (n), which denotes the number of electrons per site. Special attention was set in one-quarter-filled (n = 1) and half-filled (n = 2) bands. The results are presented by varying Coulomb repulsion (U), Hund’s coupling (JH), external magnetic field (B), and orbital energy splitting (Δϵ). For the one-quarter-filled band, an intrasite magnetic disorder (γiiαβ≈0) begins to form for large values of U/t, which is interpreted as a possible signature of a resonating valence bond state. Full orbital polarization (γiiαβ=0.25) with intersite antiferromagnetic (AFM) order (γijαβ=−0.25) was observed in the half-filled band for U/t ≫ 1, indicating that the two-orbital Hubbard model can be mapped to an AFM Heisenberg model with S = 1. The increase of JH is conductive to insulating and metallic phases for half- and one-quarter-filled bands, respectively. For a fractional n, the honeycomb lattice can exhibit spin-glass-like behavior, predominating as a disordered magnetic system characterized by random values of γijαβ. The magnetic field induced a reduction in Δc, which became zero at the critical external magnetic field. Twisted bilayer graphene (TBG) exhibits approximately flat electronic bands at magic angles and interesting correlated phenomena, such as unconventional superconductivity and correlated insulating states around n = 1 and n = 2, respectively. The dominance of electron–electron interactions in TBG makes the Hubbard model, in various versions (extended or multi-orbital), offer a practical, structure-scale account for investigating many-body effects in large moiré unit cells, where first-principles density-functional theory calculations are computationally challenging.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"244 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138855","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 : 2026-02-08DOI: 10.1021/acs.jpcc.5c08226
Bin Feng,Haochen Sun,Yilin Zhao,Wei Wang,Yiming Zhao,Aimin Ge
The formation of the solid-electrolyte interphase (SEI) plays a critical role in the electrochemical performance and cycling stability of organic anode materials in lithium-ion batteries. In this study, we employ operando attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to investigate the real-time dynamics of SEI formation on polyimide-based organic anodes during charging–discharging cycles. By comparing two commonly used carbonate-based and ether-based electrolytes, we reveal distinct differences in the composition and characteristics of the SEI. These distinct SEI characteristics lead to markedly different electrochemical performances. In ether-based electrolytes, the SEI is predominantly inorganic, facilitating efficient ion transport. The rapid capacity fade is predominated by the irreversible lithium-ion insertion reactions of aromatic ring structures. On the other hand, in carbonate-based electrolytes, the SEI is rich in organic components, leading to higher impedance. In this case, both irreversible carbonyl enolization and lithium-ion insertion into aromatic rings contribute to the rapid capacity fade.
{"title":"The Influence of the Solid-Electrolyte Interphase on Polyimide Anodes Probed by Operando Infrared Spectroscopy","authors":"Bin Feng,Haochen Sun,Yilin Zhao,Wei Wang,Yiming Zhao,Aimin Ge","doi":"10.1021/acs.jpcc.5c08226","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c08226","url":null,"abstract":"The formation of the solid-electrolyte interphase (SEI) plays a critical role in the electrochemical performance and cycling stability of organic anode materials in lithium-ion batteries. In this study, we employ operando attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to investigate the real-time dynamics of SEI formation on polyimide-based organic anodes during charging–discharging cycles. By comparing two commonly used carbonate-based and ether-based electrolytes, we reveal distinct differences in the composition and characteristics of the SEI. These distinct SEI characteristics lead to markedly different electrochemical performances. In ether-based electrolytes, the SEI is predominantly inorganic, facilitating efficient ion transport. The rapid capacity fade is predominated by the irreversible lithium-ion insertion reactions of aromatic ring structures. On the other hand, in carbonate-based electrolytes, the SEI is rich in organic components, leading to higher impedance. In this case, both irreversible carbonyl enolization and lithium-ion insertion into aromatic rings contribute to the rapid capacity fade.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"23 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138856","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}
The energy release rate of ammonium perchlorate (AP) is crucial for the detonation performance of both composite explosives and propellant systems. This work systematically investigates how 15N-substitution influences the structure, thermal decomposition, and microdetonation properties of AP. Structural analyses reveal that while 15N-substitution preserves the crystal packing model, it induces a slight elongation of the 15N–H bonds and a marginal increase in crystal density. Thermal analysis shows that the fundamental decomposition pathway remains unchanged; however, the apparent activation energy is significantly reduced from 68.15 kJ/mol (raw AP) to 45.52 kJ/mol for 15N-AP. This reduction demonstrates a pronounced reverse kinetic isotope effect (KIE) on proton transfer between NH4+ and ClO4–, which accelerates low-temperature decomposition. Laser-driven shock wave tests further confirm that 15N-AP exhibits a higher initial shock wave velocity and enhanced energy release intensity. Collectively, these findings highlight 15N-substitution as a novel and effective strategy for modulating energy release, offering a promising approach to amplify the performance of energetic formulations via isotopic substitution engineering.
{"title":"Reverse 15N Kinetic Isotope Effect Amplifies the Energy Release of Ammonium Perchlorate","authors":"Yilin Cao, Wei Wang, Ziping Yin, Zhe Zhai, Guanchen Shen, Jiaxin Wu, Wen Lei, Pan Chen, Zhaocong Shang, Zihui Meng, Chuan Xiao","doi":"10.1021/acs.jpcc.5c08282","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c08282","url":null,"abstract":"The energy release rate of ammonium perchlorate (AP) is crucial for the detonation performance of both composite explosives and propellant systems. This work systematically investigates how <sup>15</sup>N-substitution influences the structure, thermal decomposition, and microdetonation properties of AP. Structural analyses reveal that while <sup>15</sup>N-substitution preserves the crystal packing model, it induces a slight elongation of the <sup>15</sup>N–H bonds and a marginal increase in crystal density. Thermal analysis shows that the fundamental decomposition pathway remains unchanged; however, the apparent activation energy is significantly reduced from 68.15 kJ/mol (raw AP) to 45.52 kJ/mol for <sup>15</sup>N-AP. This reduction demonstrates a pronounced reverse kinetic isotope effect (KIE) on proton transfer between NH<sub>4</sub><sup>+</sup> and ClO<sub>4</sub><sup>–</sup>, which accelerates low-temperature decomposition. Laser-driven shock wave tests further confirm that <sup>15</sup>N-AP exhibits a higher initial shock wave velocity and enhanced energy release intensity. Collectively, these findings highlight <sup>15</sup>N-substitution as a novel and effective strategy for modulating energy release, offering a promising approach to amplify the performance of energetic formulations via isotopic substitution engineering.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"241 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135313","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 : 2026-02-06DOI: 10.1021/acs.jpcc.5c07119
Pablo Bastante, Ross J. Davidson, Yahia Chelli, Abdalghani H. S. Daaoub, Pilar Cea, Santiago Martin, Andrei S. Batsanov, Sara Sangtarash, Hatef Sadeghi, Martin R. Bryce, Nicolas Agrait
The present work provides insight into the effect of connectivity within isomeric 3,5-bis(pyridin-2-yl)phenyl (N^C^N) platinum and palladium complexes on their electron transmission properties within gold|molecule|gold junctions. The ligands 3,5-bis(4-(methylthio)pyridin-2-yl)phenyl hexanoate (LmH) and 3,5-bis(5-(methylthio)pyridin-2-yl)phenyl hexanoate (LpH) were synthesized and coordinated with either PtCl or PdCl to form complexes Ptm, Ptp, Pdm and Pdp. X-ray photoelectron spectroscopy (XPS) measurements evaluated the contacting modes of the molecules in the junctions. A combination of scanning tunneling microscopy-break junction (STM-BJ) measurements and density functional theory (DFT) calculations demonstrate that for the single-molecule S···S contacted junctions metal coordination enhanced the conductance compared with the free ligands. Notably, the higher degree of orbital mixing between the metal center and the ligand π-orbitals in the metal complexes plays a greater role than quantum interference to the extent that the complexes that incorporate ligands substituted with thiomethyl groups in meta positions relative to the pyridine-benzene linkages have a higher conductance than their para-analogs, e.g., Ptp −3.8 log(G/G0) and Ptm −3.3 log(G/G0), in contrast to the usual conductance trend (para > meta) for purely organic π-electron systems.
{"title":"Experimental and Theoretical Studies of Isomeric Metal (N^C^N)Cl Coordination Complexes (Metal = Pt, Pd) with Multiple Conductance Pathways in Single-Molecule Junctions","authors":"Pablo Bastante, Ross J. Davidson, Yahia Chelli, Abdalghani H. S. Daaoub, Pilar Cea, Santiago Martin, Andrei S. Batsanov, Sara Sangtarash, Hatef Sadeghi, Martin R. Bryce, Nicolas Agrait","doi":"10.1021/acs.jpcc.5c07119","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c07119","url":null,"abstract":"The present work provides insight into the effect of connectivity within isomeric 3,5-bis(pyridin-2-yl)phenyl (N^C^N) platinum and palladium complexes on their electron transmission properties within gold|molecule|gold junctions. The ligands 3,5-bis(4-(methylthio)pyridin-2-yl)phenyl hexanoate (<b>L</b><sup><b>m</b></sup>H) and 3,5-bis(5-(methylthio)pyridin-2-yl)phenyl hexanoate (<b>L</b><sup><b>p</b></sup>H) were synthesized and coordinated with either PtCl or PdCl to form complexes <b>Pt</b><sup><b>m</b></sup>, <b>Pt</b><sup><b>p</b></sup>, <b>Pd</b><sup><b>m</b></sup> and <b>Pd</b><sup><b>p</b></sup>. X-ray photoelectron spectroscopy (XPS) measurements evaluated the contacting modes of the molecules in the junctions. A combination of scanning tunneling microscopy-break junction (STM-BJ) measurements and density functional theory (DFT) calculations demonstrate that for the single-molecule S···S contacted junctions metal coordination enhanced the conductance compared with the free ligands. Notably, the higher degree of orbital mixing between the metal center and the ligand π-orbitals in the metal complexes plays a greater role than quantum interference to the extent that the complexes that incorporate ligands substituted with thiomethyl groups in <i>meta</i> positions relative to the pyridine-benzene linkages have a higher conductance than their <i>para</i>-analogs, e.g., <b>Pt</b><sup><b>p</b></sup> −3.8 log(<i>G</i>/<i>G</i><sub>0</sub>) and <b>Pt</b><sup><b>m</b></sup> −3.3 log(<i>G</i>/<i>G</i><sub>0</sub>), in contrast to the usual conductance trend (<i>para</i> > <i>meta</i>) for purely organic π-electron systems.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"177 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122389","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 : 2026-02-06DOI: 10.1021/acs.jpcc.5c07042
Ga-Un Jeong, Ryan Morelock, Soumendu Bagchi, Nadire Nayir, Adri C.T. van Duin, Panchapakesan Ganesh
Bismuth selenide (Bi2Se3) is a widely studied topological insulator and thermoelectric material whose properties are highly sensitive to crystal quality, defects, and stoichiometry. Recrystallization is an effective method of improving the crystal quality of materials, yet traditional experimental approaches are time-consuming and resource-intensive and often rely on trial and error. This work presents a new Bi/Se ReaxFF force field with the ability to recrystallize bulk Bi2Se3 into van der Waals (vdW)-layered phases under various thermal and kinetic conditions. The force field is parameterized using a diverse quantum mechanical data set, which includes formation energies of bulk layered and nonlayered Bi–Se phases, the energy–volume equation of state, point defect formation energies, the composition-dependent energetic stability trends of high-temperature BixSey clusters, and amorphous Bi2Se3 structures sampled from melt-quench molecular dynamics simulations. Our simulations reveal that structural characteristics of the resulting recrystallized vdW materials, such as stacking order and stoichiometry, depend on melt-quenching processing parameters such as the cooling rate and annealing temperature. This novel force field constitutes a predictive framework for the structural tuning of complex Bi–Se vdW materials through recrystallization conditions, laying a foundation for computational design of a much wider selection of chalcogenides.
{"title":"Development of a ReaxFF Reactive Force Field for the Crystallization of van der Waals-Layered Bismuth Selenide","authors":"Ga-Un Jeong, Ryan Morelock, Soumendu Bagchi, Nadire Nayir, Adri C.T. van Duin, Panchapakesan Ganesh","doi":"10.1021/acs.jpcc.5c07042","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c07042","url":null,"abstract":"Bismuth selenide (Bi<sub>2</sub>Se<sub>3</sub>) is a widely studied topological insulator and thermoelectric material whose properties are highly sensitive to crystal quality, defects, and stoichiometry. Recrystallization is an effective method of improving the crystal quality of materials, yet traditional experimental approaches are time-consuming and resource-intensive and often rely on trial and error. This work presents a new Bi/Se ReaxFF force field with the ability to recrystallize bulk Bi<sub>2</sub>Se<sub>3</sub> into van der Waals (vdW)-layered phases under various thermal and kinetic conditions. The force field is parameterized using a diverse quantum mechanical data set, which includes formation energies of bulk layered and nonlayered Bi–Se phases, the energy–volume equation of state, point defect formation energies, the composition-dependent energetic stability trends of high-temperature Bi<sub><i>x</i></sub>Se<sub><i>y</i></sub> clusters, and amorphous Bi<sub>2</sub>Se<sub>3</sub> structures sampled from melt-quench molecular dynamics simulations. Our simulations reveal that structural characteristics of the resulting recrystallized vdW materials, such as stacking order and stoichiometry, depend on melt-quenching processing parameters such as the cooling rate and annealing temperature. This novel force field constitutes a predictive framework for the structural tuning of complex Bi–Se vdW materials through recrystallization conditions, laying a foundation for computational design of a much wider selection of chalcogenides.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"311 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135328","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}
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