Xiao-Fang Li, Jing-Hua Guo, Ningning Zhang, Gang Chen
In this study, we employed the first-principles and real-time time-dependent density functional theory (rt-TDDFT) calculations to investigate the mechanism of visible-light-driven photocatalytic H2 production on transition-metal loaded BTEA-COF. Among 11 metallic elements screened, Pt is identified as the optimal modifier. Pt loading significantly improves the photocatalytic performance by: (1) reducing the Gibbs free energy of hydrogen by 38% to 0.19 eV, (2) extending the optical absorption edge from 441 nm (2.81 eV) to 576 nm (2.15 eV) via metal-to-ligand charge transfer, and (3) enhancing the density of photogenerated electron and suppressing the recombination of charge carriers. Rt-TDDFT simulations of the H2O@Pt/BTEA-COF interface reveal the femtosecond-scale dynamics of water photolysis. The process is dominated by electron transfer from the Pt/BTEA-COF system to the adsorbed water molecule, facilitating O-H bond cleavage at ~30 fs. The Pt atom acts as a dual-function charge pump, mediating both electron and hole transfer. These findings provide fundamental insights into the superior activity of single-atom catalysts and establish design principles for developing high-efficiency COF-based photocatalytic systems.
{"title":"Single-atom loaded BTEA-COF for enhanced visible-light photocatalytic H2 production: Insights from first-principles and real-time TDDFT calculations","authors":"Xiao-Fang Li, Jing-Hua Guo, Ningning Zhang, Gang Chen","doi":"10.1039/d5cp04147c","DOIUrl":"https://doi.org/10.1039/d5cp04147c","url":null,"abstract":"In this study, we employed the first-principles and real-time time-dependent density functional theory (rt-TDDFT) calculations to investigate the mechanism of visible-light-driven photocatalytic H2 production on transition-metal loaded BTEA-COF. Among 11 metallic elements screened, Pt is identified as the optimal modifier. Pt loading significantly improves the photocatalytic performance by: (1) reducing the Gibbs free energy of hydrogen by 38% to 0.19 eV, (2) extending the optical absorption edge from 441 nm (2.81 eV) to 576 nm (2.15 eV) via metal-to-ligand charge transfer, and (3) enhancing the density of photogenerated electron and suppressing the recombination of charge carriers. Rt-TDDFT simulations of the H2O@Pt/BTEA-COF interface reveal the femtosecond-scale dynamics of water photolysis. The process is dominated by electron transfer from the Pt/BTEA-COF system to the adsorbed water molecule, facilitating O-H bond cleavage at ~30 fs. The Pt atom acts as a dual-function charge pump, mediating both electron and hole transfer. These findings provide fundamental insights into the superior activity of single-atom catalysts and establish design principles for developing high-efficiency COF-based photocatalytic systems.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"11 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138972","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}
Attila Á. Dékány, Balázs József J. Molnár, Gabor Czako
We conducted mode-specific quasi-classical trajectory (QCT) simulations of the gas-phase F– + SiH3Cl reaction employing a full-dimensional, coupled-cluster-quality potential energy surface. Simulations were performed at collision energies ranging from 1 to 40 kcal/mol, with one vibrational quantum selectively excited in each of the six distinct vibrational modes of SiH3Cl, namely the SiCl stretching, SiH3 rocking, SiH3 umbrella and deformation modes, and symmetric and asymmetric SiH stretching. Multiple reaction channels were analyzed, including chloride-ion substitution via inversion and retention pathways, proton abstraction, hydrogen chloride (HCl) formation, hydride-ion substitution, molecular-hydrogen production, and FHCl– formation. From the QCT simulations, reaction probabilities, integral cross sections, initial attack angle and scattering angle distributions, and product energy distributions (internal, translational, vibrational, and rotational) were derived. Notably, excitation of SiH stretching modes led to a modest reduction in cross sections for chloride-ion substitution, whereas other product channels showed mild to significant enhancements. Excitation of other vibrational modes minimally impacted chloride-substitution and proton-abstraction cross sections, but significantly, although less markedly than SiH stretching modes, enhanced the remaining product channels. The initial attack angle and scattering angle distributions are not affected by vibrational excitations for all product channels, and the post-reaction energy distributions showed minimal effects.
{"title":"Mode-specific quasi-classical dynamics of the F– + SiH3Cl system","authors":"Attila Á. Dékány, Balázs József J. Molnár, Gabor Czako","doi":"10.1039/d5cp04412j","DOIUrl":"https://doi.org/10.1039/d5cp04412j","url":null,"abstract":"We conducted mode-specific quasi-classical trajectory (QCT) simulations of the gas-phase F– + SiH3Cl reaction employing a full-dimensional, coupled-cluster-quality potential energy surface. Simulations were performed at collision energies ranging from 1 to 40 kcal/mol, with one vibrational quantum selectively excited in each of the six distinct vibrational modes of SiH3Cl, namely the SiCl stretching, SiH3 rocking, SiH3 umbrella and deformation modes, and symmetric and asymmetric SiH stretching. Multiple reaction channels were analyzed, including chloride-ion substitution via inversion and retention pathways, proton abstraction, hydrogen chloride (HCl) formation, hydride-ion substitution, molecular-hydrogen production, and FHCl– formation. From the QCT simulations, reaction probabilities, integral cross sections, initial attack angle and scattering angle distributions, and product energy distributions (internal, translational, vibrational, and rotational) were derived. Notably, excitation of SiH stretching modes led to a modest reduction in cross sections for chloride-ion substitution, whereas other product channels showed mild to significant enhancements. Excitation of other vibrational modes minimally impacted chloride-substitution and proton-abstraction cross sections, but significantly, although less markedly than SiH stretching modes, enhanced the remaining product channels. The initial attack angle and scattering angle distributions are not affected by vibrational excitations for all product channels, and the post-reaction energy distributions showed minimal effects.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"18 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138742","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}
Pragnya Paramita Samal, Fabian Berger, Sailaja Krishnamurty, Joachim Sauer
We employ a chemically accurate (±4 kJ mol−1) embedding approach to calculate enthalpies for CO2, N2, and H2 adsorption in the Zn2+-containing zeolites FAU and CHA, and for CO2 and H2 in the metal–organic frameworks (MOFs) Zn-MOF-74 and CALF-20. Using MP2 as the high-level method and PBE+D4 as the periodic low-level method (MP2:PBE+D4), we obtain CO2 adsorption enthalpies of −46, −34, and −36 kJ mol−1 for Zn-CHA, Zn-MOF-74, and CALF-20, respectively, all within chemical accuracy limits of the experimental values of −42, −30, and −39 kJ mol−1. For CO2 in Zn-FAU, where no experimental data exist, we provide an MP2:PBE+D4 prediction of −49 kJ mol−1. For N2, we predict MP2:PBE+D4 adsorption enthalpies of −41 and −39 kJ mol−1 in Zn-CHA and Zn-FAU, respectively. CO2 adsorption is stronger in the zeolites than in the studied MOFs. Across all systems, CO2 adsorption tends to be stronger than N2 adsorption and both are largely favoured over H2. We observe inconsistent accuracy of PBE+D4 for the two MOFs, despite their similar characteristics, underscoring the need for high-level approaches in predictive screening. Additionally, we conclude that Zn2+ cations with open coordination sites act as the primary binding sites and that these cations preferentially occupy 6-membered rings in zeolites.
{"title":"CO2, N2 and H2 adsorption in Zn2+-containing zeolites and metal–organic frameworks","authors":"Pragnya Paramita Samal, Fabian Berger, Sailaja Krishnamurty, Joachim Sauer","doi":"10.1039/d5cp04169d","DOIUrl":"https://doi.org/10.1039/d5cp04169d","url":null,"abstract":"We employ a chemically accurate (±4 kJ mol<small><sup>−1</sup></small>) embedding approach to calculate enthalpies for CO<small><sub>2</sub></small>, N<small><sub>2</sub></small>, and H<small><sub>2</sub></small> adsorption in the Zn<small><sup>2+</sup></small>-containing zeolites FAU and CHA, and for CO<small><sub>2</sub></small> and H<small><sub>2</sub></small> in the metal–organic frameworks (MOFs) Zn-MOF-74 and CALF-20. Using MP2 as the high-level method and PBE+D4 as the periodic low-level method (MP2:PBE+D4), we obtain CO<small><sub>2</sub></small> adsorption enthalpies of −46, −34, and −36 kJ mol<small><sup>−1</sup></small> for Zn-CHA, Zn-MOF-74, and CALF-20, respectively, all within chemical accuracy limits of the experimental values of −42, −30, and −39 kJ mol<small><sup>−1</sup></small>. For CO<small><sub>2</sub></small> in Zn-FAU, where no experimental data exist, we provide an MP2:PBE+D4 prediction of −49 kJ mol<small><sup>−1</sup></small>. For N<small><sub>2</sub></small>, we predict MP2:PBE+D4 adsorption enthalpies of −41 and −39 kJ mol<small><sup>−1</sup></small> in Zn-CHA and Zn-FAU, respectively. CO<small><sub>2</sub></small> adsorption is stronger in the zeolites than in the studied MOFs. Across all systems, CO<small><sub>2</sub></small> adsorption tends to be stronger than N<small><sub>2</sub></small> adsorption and both are largely favoured over H<small><sub>2</sub></small>. We observe inconsistent accuracy of PBE+D4 for the two MOFs, despite their similar characteristics, underscoring the need for high-level approaches in predictive screening. Additionally, we conclude that Zn<small><sup>2+</sup></small> cations with open coordination sites act as the primary binding sites and that these cations preferentially occupy 6-membered rings in zeolites.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"57 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138741","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}
Kai-Yin Wu, Zi-Yang Feng, Zhi Li, Hazar Guesmi, Laurent Piccolo, Lixin Chen, Chao Su, Beibei Xiao
MXenes, a novel class of two-dimensional transition metal carbides, nitrides or carbonitrides, have emerged as promising supports for single-atom catalysts due to their tunable structural and electronic properties. Using density functional theory calculations, we investigate ordered, termination-free Mo-based bimetallic MXenes (o-Mo2M"2C3 and o-Mo2M"C2 with M"= Ti, Zr, Hf, V, Nb and Ta) as materials to stabilize platinum-group-metal (PGM) single atoms at Mo vacancies. Compared with the corresponding Mo-only MXenes, introducing a second metal component M" strengthens PGM anchoring and increases sintering resistance, which we attribute to a ligand effect that enhances PGM-C covalency and reorganizes the PGM d states. This stabilization is further captured by a combined electronic descriptor δ = εp ‒ εd. Here, δ is defined as the difference between the p band center (εp) of the C atoms adjacent to the PGM and the d band center (εd) of the PGM atom. This descriptor δ shows a strong correlation with the binding energetics across both considered MXenes families. To assess reactivity trends, we use CO, CH3 and NH3 adsorption strength, highlighting a stability-reactivity trend. An XGBoost-based machine learning analysis further indicates that adsorption energies are governed by multiple electronic descriptors (beyond εd), with the average electronegativity of PGM-MXene system (χavg) contributing to the trends. This study provides new atomic-level understanding into the rational design principle for stabilizing atomically dispersed SACs on MXenes and provides guidelines for experimental synthesis.
{"title":"DFT insight into the stability of single metal atoms on Mo-based o-MXenes driven by the ligand effect","authors":"Kai-Yin Wu, Zi-Yang Feng, Zhi Li, Hazar Guesmi, Laurent Piccolo, Lixin Chen, Chao Su, Beibei Xiao","doi":"10.1039/d6cp00177g","DOIUrl":"https://doi.org/10.1039/d6cp00177g","url":null,"abstract":"MXenes, a novel class of two-dimensional transition metal carbides, nitrides or carbonitrides, have emerged as promising supports for single-atom catalysts due to their tunable structural and electronic properties. Using density functional theory calculations, we investigate ordered, termination-free Mo-based bimetallic MXenes (o-Mo2M\"2C3 and o-Mo2M\"C2 with M\"= Ti, Zr, Hf, V, Nb and Ta) as materials to stabilize platinum-group-metal (PGM) single atoms at Mo vacancies. Compared with the corresponding Mo-only MXenes, introducing a second metal component M\" strengthens PGM anchoring and increases sintering resistance, which we attribute to a ligand effect that enhances PGM-C covalency and reorganizes the PGM d states. This stabilization is further captured by a combined electronic descriptor δ = εp ‒ εd. Here, δ is defined as the difference between the p band center (εp) of the C atoms adjacent to the PGM and the d band center (εd) of the PGM atom. This descriptor δ shows a strong correlation with the binding energetics across both considered MXenes families. To assess reactivity trends, we use CO, CH3 and NH3 adsorption strength, highlighting a stability-reactivity trend. An XGBoost-based machine learning analysis further indicates that adsorption energies are governed by multiple electronic descriptors (beyond εd), with the average electronegativity of PGM-MXene system (χavg) contributing to the trends. This study provides new atomic-level understanding into the rational design principle for stabilizing atomically dispersed SACs on MXenes and provides guidelines for experimental synthesis.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"311 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135318","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}
Carbene-metal-amide based thermally activated delayed fluorescence (CMA-TADF) compounds are promising emerging metal-organic materials for OLEDs. However, there is a lack of systematic studies on the influence of external electric fields (EEFs) on the underlying photophysical mechanisms of conformationally distinct CMA complexes. In this work, we employ density functional theory (DFT) and time-dependent DFT (TD-DFT) methods to elucidate how EEFs of specific orientation and magnitude govern the excited-state properties and dynamics of coplanar (CAAC-Au-Ptz-1) versus perpendicular (CAAC-Au-Ptz-2) conformations. The results indicate that in the CAAC-Au-Ptz-1 conformation, the delayed fluorescence quantum yield (Ф DF ) increased by 16.41%. This is primarily due to EEF-induced elevation of triplet energy, which reduced singlet-triplet energy gap (ΔE ST ) by 0.052 eV and enhanced spin-orbit coupling (SOC) effect. In combination with other contributing factors, these alterations collectively drove a series of corresponding modulations in both radiative and nonradiative rates. For the perpendicular conformation (CAAC-Au-Ptz-2), although ΔE ST rises under EEF, this effect is counterbalanced by a concurrent increase in SOC matrix element (SOCME).Consequently, the resulting Ф DF remains around 95%, matching the performance observed in the absence of EEF. These findings on conformational and EEF effects pave the way for developing high-performance luminescent materials and novel design strategies.
{"title":"Rational Design of Local Electric Fields: An Effective Strategy to Modulate Thermally Activated Delayed Fluorescence in Carbene-Gold(I)-Amide Complexes","authors":"Ziye Ning, Surui Zhao, Yizi Meng, YanYing Zhang, Bowen Tang, Leilei Cui, Xiaoning Liu, Lingling Lv","doi":"10.1039/d5cp04864h","DOIUrl":"https://doi.org/10.1039/d5cp04864h","url":null,"abstract":"Carbene-metal-amide based thermally activated delayed fluorescence (CMA-TADF) compounds are promising emerging metal-organic materials for OLEDs. However, there is a lack of systematic studies on the influence of external electric fields (EEFs) on the underlying photophysical mechanisms of conformationally distinct CMA complexes. In this work, we employ density functional theory (DFT) and time-dependent DFT (TD-DFT) methods to elucidate how EEFs of specific orientation and magnitude govern the excited-state properties and dynamics of coplanar (CAAC-Au-Ptz-1) versus perpendicular (CAAC-Au-Ptz-2) conformations. The results indicate that in the CAAC-Au-Ptz-1 conformation, the delayed fluorescence quantum yield (Ф DF ) increased by 16.41%. This is primarily due to EEF-induced elevation of triplet energy, which reduced singlet-triplet energy gap (ΔE ST ) by 0.052 eV and enhanced spin-orbit coupling (SOC) effect. In combination with other contributing factors, these alterations collectively drove a series of corresponding modulations in both radiative and nonradiative rates. For the perpendicular conformation (CAAC-Au-Ptz-2), although ΔE ST rises under EEF, this effect is counterbalanced by a concurrent increase in SOC matrix element (SOCME).Consequently, the resulting Ф DF remains around 95%, matching the performance observed in the absence of EEF. These findings on conformational and EEF effects pave the way for developing high-performance luminescent materials and novel design strategies.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"132 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135319","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}
With the increasing demand for hydrogen (H2) as a clean energy source, the use of efficient methods for its purification has become increasingly important, especially due to the presence of carbon dioxide (CO2) as one of the main impurities in the hydrogen production process. In this study, a combined approach including molecular simulation and Maxwell–Stefan modeling was used to analyze the transport behavior of CO2 and H2 in P-HAB-6FDA membranes. The simulation results show a significant difference between pure gas and mixed gas conditions. While hydrogen has a higher permeability in pure gas conditions, in mixed gas systems, carbon dioxide takes over the adsorption process and practically prevents the adsorption and transport of hydrogen. Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were used to determine the adsorption and diffusion coefficients, and the Maxwell–Stefan model was used to predict the gas permeability and selectivity. Also, under mixed gas conditions, the permeability of CO2 exceeds that of H2, which is in contrast to the behavior under pure gas conditions and is due to the strong adsorption tendency of CO2. Lower temperature improves membrane performance by simultaneously increasing CO2 adsorption and facilitating hydrogen diffusion. These findings highlight the significant difference between the transport mechanisms under pure and mixed gas conditions and confirm the efficiency of 6FDA-based membranes in selective hydrogen purification and CO2 separation; and advance our understanding of the development of membrane-based gas separation technologies.
{"title":"From first principal study to continuum modeling: competitive gas adsorption in microporous PIM membranes","authors":"Behrouz Bayati, Masoumeh Nourimotlagh, Catia Algieri, Mohammadmehdi Moradkhani","doi":"10.1039/d5cp02643a","DOIUrl":"https://doi.org/10.1039/d5cp02643a","url":null,"abstract":"With the increasing demand for hydrogen (H<small><sub>2</sub></small>) as a clean energy source, the use of efficient methods for its purification has become increasingly important, especially due to the presence of carbon dioxide (CO<small><sub>2</sub></small>) as one of the main impurities in the hydrogen production process. In this study, a combined approach including molecular simulation and Maxwell–Stefan modeling was used to analyze the transport behavior of CO<small><sub>2</sub></small> and H<small><sub>2</sub></small> in P-HAB-6FDA membranes. The simulation results show a significant difference between pure gas and mixed gas conditions. While hydrogen has a higher permeability in pure gas conditions, in mixed gas systems, carbon dioxide takes over the adsorption process and practically prevents the adsorption and transport of hydrogen. Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were used to determine the adsorption and diffusion coefficients, and the Maxwell–Stefan model was used to predict the gas permeability and selectivity. Also, under mixed gas conditions, the permeability of CO<small><sub>2</sub></small> exceeds that of H<small><sub>2</sub></small>, which is in contrast to the behavior under pure gas conditions and is due to the strong adsorption tendency of CO<small><sub>2</sub></small>. Lower temperature improves membrane performance by simultaneously increasing CO<small><sub>2</sub></small> adsorption and facilitating hydrogen diffusion. These findings highlight the significant difference between the transport mechanisms under pure and mixed gas conditions and confirm the efficiency of 6FDA-based membranes in selective hydrogen purification and CO<small><sub>2</sub></small> separation; and advance our understanding of the development of membrane-based gas separation technologies.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"89 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122436","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}
We present the extension of the system of error-consistent segmented contracted Gaussian basis sets (Karlsruhe def2-bases [Weigend and Ahlrichs, Phys. Chem. Chem. Phys., 2005, 7, 3297–3305]) for the lanthanide large core effective core potentials (lcECPs) designed by Dolg, Stoll, Savin and Preuss, Theor. Chim. Acta, 1989, 75, 173–194. For La–Lu, sets of double zeta (“split”, S), triple zeta (TZ), and quadruple zeta (QZ) valence (V) quality were optimized in atomic Hartree–Fock calculations for each of the different lcECPs that model the occupations fn−k, k = 0, 1, 2, and n being the (typical) ground state f shell occupation; e.g. for Pr, n = 3, for each of the occupations f3, f2, and f1, an SV, TZV, and QZV basis were optimized and termed lcecp-k-XV (k = 0, 1, 2, X = S, TZ, QZ). Polarization functions for the quadruple zeta valence bases were taken from Weigand, Cao, Yang, and Dolg, Theor. Chem. Acc., 2010, 126, 117–127, for the smaller basis sets they were appropriately reduced. The conformity with the def2-series in regards to error-consistency was assessed for a set of 120 molecules by comparing distances, bond angles, vibration frequencies and exchange reaction energies in regards to the basis set limit and also to all-electron scalar relativistic calculations.
{"title":"Error-consistent basis sets for large-core ECPs for elements La–Lu","authors":"Marcel Lukanowski, Florian Weigend","doi":"10.1039/d5cp04944j","DOIUrl":"https://doi.org/10.1039/d5cp04944j","url":null,"abstract":"We present the extension of the system of error-consistent segmented contracted Gaussian basis sets (Karlsruhe def2-bases [Weigend and Ahlrichs, <em>Phys. Chem. Chem. Phys.</em>, 2005, <strong>7</strong>, 3297–3305]) for the lanthanide large core effective core potentials (lcECPs) designed by Dolg, Stoll, Savin and Preuss, <em>Theor. Chim. Acta</em>, 1989, <strong>75</strong>, 173–194. For La–Lu, sets of double zeta (“split”, S), triple zeta (TZ), and quadruple zeta (QZ) valence (V) quality were optimized in atomic Hartree–Fock calculations for each of the different lcECPs that model the occupations f<small><sup><em>n</em>−<em>k</em></sup></small>, <em>k</em> = 0, 1, 2, and <em>n</em> being the (typical) ground state f shell occupation; <em>e.g.</em> for Pr, <em>n</em> = 3, for each of the occupations f<small><sup>3</sup></small>, f<small><sup>2</sup></small>, and f<small><sup>1</sup></small>, an SV, TZV, and QZV basis were optimized and termed lcecp-<em>k</em>-XV (<em>k</em> = 0, 1, 2, X = S, TZ, QZ). Polarization functions for the quadruple zeta valence bases were taken from Weigand, Cao, Yang, and Dolg, <em>Theor. Chem. Acc.</em>, 2010, <strong>126</strong>, 117–127, for the smaller basis sets they were appropriately reduced. The conformity with the def2-series in regards to error-consistency was assessed for a set of 120 molecules by comparing distances, bond angles, vibration frequencies and exchange reaction energies in regards to the basis set limit and also to all-electron scalar relativistic calculations.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"83 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122435","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}
Hyundong Hyundong Kim, Sompriya Chatterjee, Myounwoo Kim, Yeonsig Nam, S. Mukamel, Jin Yong Lee
Differentiating histidine tautomeric states is critical for understanding their role in neurodegenerative disease pathogenesis. Shifts in tautomer equilibrium may drive protein misfolding and aggregation, suggesting potential therapeutic interventions to mitigate disease progression. However, unsubstituted histidine exhibits overlapping N K-edge peaks, making it difficult to distinguish its δ, ε, and π tautomeric forms. To achieve optimal spectral resolution, we substituted the hydrogen bonded to Cδ on the imidazole ring, minimizing degeneracy and enabling clearer peak assignments. Several substituents with varied electron-donating or electron-withdrawing properties were introduced to modify the electronic environment of the imidazole ring. Among these, substituents acting as weak or strong electron donors provided especially clear spectral differentiation across the N K-edge. Using the state-averaged restricted active space self-consistent field (SA-RASSCF) method, this study proposes X-ray absorption spectroscopy (XAS) as a viable approach to distinguish histidine tautomeric states. This strategy highlights XAS labeling as a promising tool for differentiating tautomeric structures in complex biomolecules and will provide novel insights into histidine’s role in both biological and pathological processes, ultimately informing therapeutic discovery.
{"title":"Probing Histidine Tautomer by X-ray Absorption Spectroscopy for Biological and Pathological Studies","authors":"Hyundong Hyundong Kim, Sompriya Chatterjee, Myounwoo Kim, Yeonsig Nam, S. Mukamel, Jin Yong Lee","doi":"10.1039/d5cp01475a","DOIUrl":"https://doi.org/10.1039/d5cp01475a","url":null,"abstract":"Differentiating histidine tautomeric states is critical for understanding their role in neurodegenerative disease pathogenesis. Shifts in tautomer equilibrium may drive protein misfolding and aggregation, suggesting potential therapeutic interventions to mitigate disease progression. However, unsubstituted histidine exhibits overlapping N K-edge peaks, making it difficult to distinguish its δ, ε, and π tautomeric forms. To achieve optimal spectral resolution, we substituted the hydrogen bonded to C<small><sub>δ</sub></small> on the imidazole ring, minimizing degeneracy and enabling clearer peak assignments. Several substituents with varied electron-donating or electron-withdrawing properties were introduced to modify the electronic environment of the imidazole ring. Among these, substituents acting as weak or strong electron donors provided especially clear spectral differentiation across the N K-edge. Using the state-averaged restricted active space self-consistent field (SA-RASSCF) method, this study proposes X-ray absorption spectroscopy (XAS) as a viable approach to distinguish histidine tautomeric states. This strategy highlights XAS labeling as a promising tool for differentiating tautomeric structures in complex biomolecules and will provide novel insights into histidine’s role in both biological and pathological processes, ultimately informing therapeutic discovery.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"38 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138743","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}
Jin Wang, Boxuan Xie, Xue Wu, Guangjun Tian, Liang Ma, Li Li
The electronic transport properties of molecular junctions based on four boron clusters, B32, B39, B42, and B45, that have tubular ground state structures were studied using first principles calculations and non-equilibrium Green's function simulations. Spin polarized calculations indicate that the charge transport properties are almost spin-independent at low bias voltages. In fact, only the junction based on B39 exhibits the spin polarization effect, while the other open-shell cluster (B45) shows no spin dependence due to its coupling with the electrodes. The calculated current-voltage characteristics show that the four types of molecular junctions have diverse functionalities, with the B32 and B39 junctions exhibiting current limiting features, while a clear negative differential resistance effect was found in the B42 and B45 junctions. These results suggest that molecular junctions based on boron clusters, which support rich geometrical and electronic properties, could serve as an important group of candidates for constructing functional molecular devices.
{"title":"Charge transport properties of tubular boron cluster-based molecular junctions: a first-principles study.","authors":"Jin Wang, Boxuan Xie, Xue Wu, Guangjun Tian, Liang Ma, Li Li","doi":"10.1039/d5cp04140f","DOIUrl":"https://doi.org/10.1039/d5cp04140f","url":null,"abstract":"<p><p>The electronic transport properties of molecular junctions based on four boron clusters, B<sub>32</sub>, B<sub>39</sub>, B<sub>42</sub>, and B<sub>45</sub>, that have tubular ground state structures were studied using first principles calculations and non-equilibrium Green's function simulations. Spin polarized calculations indicate that the charge transport properties are almost spin-independent at low bias voltages. In fact, only the junction based on B<sub>39</sub> exhibits the spin polarization effect, while the other open-shell cluster (B<sub>45</sub>) shows no spin dependence due to its coupling with the electrodes. The calculated current-voltage characteristics show that the four types of molecular junctions have diverse functionalities, with the B<sub>32</sub> and B<sub>39</sub> junctions exhibiting current limiting features, while a clear negative differential resistance effect was found in the B<sub>42</sub> and B<sub>45</sub> junctions. These results suggest that molecular junctions based on boron clusters, which support rich geometrical and electronic properties, could serve as an important group of candidates for constructing functional molecular devices.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146123354","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}
We report a theoretical investigation of the structural and optical responses of a molecular crystal based on a push-pull chromophore subjected to increasing isotropic pressure ranging from 1 to 30 kbar. Geometry optimizations at the DFT level reveal pronounced changes in unit cell parameters, particularly along the stacking and charge-transfer directions, accompanied by significant volume compression, reaching 17% at the highest pressure. Pressure also alters key intramolecular torsional angles and intermolecular stacking geometries, with non-linear variations and discontinuities observed in the evolution of these parameters. Time-dependent DFT calculations on pressure-adapted geometries of molecular dimers show that these structural changes lead to abrupt shifts in excited-state energies, oscillator strengths, exciton localization, and charge-transfer character. The external pressure is also shown to strongly influence the second-harmonic generation (SHG) response of the dimers, which are considered representative of the stacking arrangements in thin films. As rationalized using a truncated sum-over-states (SOS) approach, the pressure-induced variation in the SHG response is closely linked to changes in the charge-transfer character and absorption strength of a small set of low-lying excited states. Overall, our calculations indicate that increasing the external pressure from 1 to 30 kbar leads to an 11% decrease in the static first hyperpolarizability of the dimer. The dynamic first hyperpolarizability computed at an incident wavelength of 800 nm evolves non monotonically with pressure, exhibiting a maximum around 8 kbar due to resonance effects at the second harmonic, and overall reduction of 74% from 1 to 30 kbar. These results suggest that external pressure provides an effective means to modulate the nonlinear optical properties of 2D materials based on these push–pull chromophores.
{"title":"Pressure- and Aggregation-Induced Modulation of Linear and Nonlinear Optical Properties in a Push-Pull Chromophore: Insights from Computational Modelling","authors":"Josianne Owona, Selom Goto, Lionel Truflandier, Claire Tonnelé, Frederic Castet","doi":"10.1039/d5cp04030b","DOIUrl":"https://doi.org/10.1039/d5cp04030b","url":null,"abstract":"We report a theoretical investigation of the structural and optical responses of a molecular crystal based on a push-pull chromophore subjected to increasing isotropic pressure ranging from 1 to 30 kbar. Geometry optimizations at the DFT level reveal pronounced changes in unit cell parameters, particularly along the stacking and charge-transfer directions, accompanied by significant volume compression, reaching 17% at the highest pressure. Pressure also alters key intramolecular torsional angles and intermolecular stacking geometries, with non-linear variations and discontinuities observed in the evolution of these parameters. Time-dependent DFT calculations on pressure-adapted geometries of molecular dimers show that these structural changes lead to abrupt shifts in excited-state energies, oscillator strengths, exciton localization, and charge-transfer character. The external pressure is also shown to strongly influence the second-harmonic generation (SHG) response of the dimers, which are considered representative of the stacking arrangements in thin films. As rationalized using a truncated sum-over-states (SOS) approach, the pressure-induced variation in the SHG response is closely linked to changes in the charge-transfer character and absorption strength of a small set of low-lying excited states. Overall, our calculations indicate that increasing the external pressure from 1 to 30 kbar leads to an 11% decrease in the static first hyperpolarizability of the dimer. The dynamic first hyperpolarizability computed at an incident wavelength of 800 nm evolves non monotonically with pressure, exhibiting a maximum around 8 kbar due to resonance effects at the second harmonic, and overall reduction of 74% from 1 to 30 kbar. These results suggest that external pressure provides an effective means to modulate the nonlinear optical properties of 2D materials based on these push–pull chromophores.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"302 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122271","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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