Pub Date : 2025-10-25DOI: 10.1016/j.chemphys.2025.112993
Xiyao Yun , Wanxiao Guo , Shaokang Tian , Weiyi Li , Hui Fu , Yilin Fang , Zexin Jiang , Jintao Wang , Tao Wang
In this study, a ReaxFF force field was developed for the composite system comprising 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,4-polybutadiene rubber (BR), and fluoropolymer (F2604). Based on this force field, molecular dynamics (MD) simulations were employed to investigate the mechanisms by which BR and F2604 influence the thermal decomposition of HMX. The results indicate that the presence of BR and F2604 binders generally extends the decomposition duration of HMX. Throughout the reaction process, these binders facilitate the conversion of HMX decomposition intermediates into stable end products, thereby preventing the excessive accumulation of intermediates and mitigating intense interactions among them during the middle stage of decomposition. This research elucidates the role of binders in the thermal decomposition of high-energy explosives, offering novel insights and methodological approaches for future studies in this field.
{"title":"Study on the action mechanism of two typical binders on the thermal decomposition process of HMX","authors":"Xiyao Yun , Wanxiao Guo , Shaokang Tian , Weiyi Li , Hui Fu , Yilin Fang , Zexin Jiang , Jintao Wang , Tao Wang","doi":"10.1016/j.chemphys.2025.112993","DOIUrl":"10.1016/j.chemphys.2025.112993","url":null,"abstract":"<div><div>In this study, a ReaxFF force field was developed for the composite system comprising 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,4-polybutadiene rubber (BR), and fluoropolymer (F<sub>2604</sub>). Based on this force field, molecular dynamics (MD) simulations were employed to investigate the mechanisms by which BR and F<sub>2604</sub> influence the thermal decomposition of HMX. The results indicate that the presence of BR and F<sub>2604</sub> binders generally extends the decomposition duration of HMX. Throughout the reaction process, these binders facilitate the conversion of HMX decomposition intermediates into stable end products, thereby preventing the excessive accumulation of intermediates and mitigating intense interactions among them during the middle stage of decomposition. This research elucidates the role of binders in the thermal decomposition of high-energy explosives, offering novel insights and methodological approaches for future studies in this field.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112993"},"PeriodicalIF":2.4,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526391","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}
A fractal geometry approach is established to relate a heterogeneous catalyst's performance to its surface morphology. We show that the activation energy of a reaction and the pre-exponential factor are directly connected with the surface fractal dimension of a catalyst. The experimental verification of the approach is achieved using a first-order model reaction, e.g., CO oxidation over Fe2O3 nanoparticles of various morphologies. For this reaction, both pre-exponential factor and activation energy increase monotonically with the growth of the surface fractal dimension of Fe2O3 catalyst, which is in agreement with theoretical predictions.
{"title":"Relationship between the morphology and activity of a heterogeneous catalyst: A fractal geometry approach to CO oxidation over Fe2O3 nanoparticles","authors":"O.O. Zhokh , A.I. Trypolskyi , K.S. Gavrilenko , V.I. Gritsenko , I.L. Stolyarchuk , P.E. Strizhak","doi":"10.1016/j.chemphys.2025.112983","DOIUrl":"10.1016/j.chemphys.2025.112983","url":null,"abstract":"<div><div>A fractal geometry approach is established to relate a heterogeneous catalyst's performance to its surface morphology. We show that the activation energy of a reaction and the pre-exponential factor are directly connected with the surface fractal dimension of a catalyst. The experimental verification of the approach is achieved using a first-order model reaction, e.g., CO oxidation over Fe<sub>2</sub>O<sub>3</sub> nanoparticles of various morphologies. For this reaction, both pre-exponential factor and activation energy increase monotonically with the growth of the surface fractal dimension of Fe<sub>2</sub>O<sub>3</sub> catalyst, which is in agreement with theoretical predictions.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112983"},"PeriodicalIF":2.4,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-24DOI: 10.1016/j.chemphys.2025.112978
Hoang Van Ngoc , Trieu Quynh Trang
This work explores indium-doped two-dimensional zinc oxide quantum dots (2D InZnO QDs) as potential candidates for gas sensing, focusing on their interaction with NO2 and NH3. Structural, electronic, magnetic, and optical properties of pristine and adsorbed systems were investigated using Density Functional Theory (DFT) combined with machine learning approaches. Gas adsorption was found to strongly influence the physical properties, particularly in the NO2 case. NO2 adsorption reduces the bulk modulus, modifies electronic states, and introduces new features in the dielectric function and absorption spectrum, mainly in the ultraviolet-visible region. By contrast, NH3 adsorption induces only minor perturbations, reflecting weak binding. Joint density of states (JDOS) analysis indicates dominant electron–hole transitions near 13 eV, with NO2 adsorption leading to broader transitions and anisotropic optical responses. These results highlight the tunability of optoelectronic properties in 2D InZnO QDs through gas adsorption, supporting their potential in nanoscale sensing applications.
{"title":"Indium-doped 2D ZnO quantum dots for NO2 and NH3 detection: A first-principles and machine learning study","authors":"Hoang Van Ngoc , Trieu Quynh Trang","doi":"10.1016/j.chemphys.2025.112978","DOIUrl":"10.1016/j.chemphys.2025.112978","url":null,"abstract":"<div><div>This work explores indium-doped two-dimensional zinc oxide quantum dots (2D InZnO QDs) as potential candidates for gas sensing, focusing on their interaction with NO<sub>2</sub> and NH<sub>3</sub>. Structural, electronic, magnetic, and optical properties of pristine and adsorbed systems were investigated using Density Functional Theory (DFT) combined with machine learning approaches. Gas adsorption was found to strongly influence the physical properties, particularly in the NO<sub>2</sub> case. NO<sub>2</sub> adsorption reduces the bulk modulus, modifies electronic states, and introduces new features in the dielectric function and absorption spectrum, mainly in the ultraviolet-visible region. By contrast, NH<sub>3</sub> adsorption induces only minor perturbations, reflecting weak binding. Joint density of states (JDOS) analysis indicates dominant electron–hole transitions near 13 eV, with NO<sub>2</sub> adsorption leading to broader transitions and anisotropic optical responses. These results highlight the tunability of optoelectronic properties in 2D InZnO QDs through gas adsorption, supporting their potential in nanoscale sensing applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112978"},"PeriodicalIF":2.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360902","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}
Luminescence and thermoresponsive properties of Mg3WO6:Tb3+ double perovskites were investigated for optical thermometry. Rietveld refinement of X-ray diffraction (XRD) data confirmed the formation of monoclinic crystallites. Photoluminescence (PL) response under various excitation wavelengths revealed a tunable color emission, ascribed to host emission and characteristic Tb3+ transitions. The optimal PL intensity was achieved with 0.4 mol% Tb3+ doping, beyond which concentration quenching occurred due to dipole-dipole interactions. The temperature-dependent PL (TDPL) spectra demonstrated that the 5D4–7F6 and 5D4–7F5 transitions of Tb3+ displaying different responses to temperature, exhibiting thermal dependence. Utilizing the fluorescence intensity ratio (FIR) from the TDPL spectra within 303–513 K, the temperature reading properties of the Mg3WO6:0.4 % Tb3+ phosphor was examined. Subsequently, highest relative sensitivity SR (0.62 % K−1) was obtained at 303 K. Furthermore, the FIR calculated from the TDPL spectra obtained during heating and cooling processes, along with repeatability cycles, confirmed the reliability and repeatability of the temperature sensor.
{"title":"Luminescence and thermometric performance of Tb(III) activated Mg3WO6 double perovskite phosphor","authors":"Naresh Degda , Nimesh Patel , Yashesh Gandhi , K.V.R. Murthy , M. Srinivas","doi":"10.1016/j.chemphys.2025.112985","DOIUrl":"10.1016/j.chemphys.2025.112985","url":null,"abstract":"<div><div>Luminescence and thermoresponsive properties of Mg<sub>3</sub>WO<sub>6</sub>:Tb<sup>3+</sup> double perovskites were investigated for optical thermometry. Rietveld refinement of X-ray diffraction (XRD) data confirmed the formation of monoclinic crystallites. Photoluminescence (PL) response under various excitation wavelengths revealed a tunable color emission, ascribed to host emission and characteristic Tb<sup>3+</sup> transitions. The optimal PL intensity was achieved with 0.4 mol% Tb<sup>3+</sup> doping, beyond which concentration quenching occurred due to dipole-dipole interactions. The temperature-dependent PL (TDPL) spectra demonstrated that the <sup>5</sup>D<sub>4</sub>–<sup>7</sup>F<sub>6</sub> and <sup>5</sup>D<sub>4</sub>–<sup>7</sup>F<sub>5</sub> transitions of Tb<sup>3+</sup> displaying different responses to temperature, exhibiting thermal dependence. Utilizing the fluorescence intensity ratio (FIR) from the TDPL spectra within 303–513 K, the temperature reading properties of the Mg<sub>3</sub>WO<sub>6</sub>:0.4 % Tb<sup>3+</sup> phosphor was examined. Subsequently, highest relative sensitivity S<sub>R</sub> (0.62 % K<sup>−1</sup>) was obtained at 303 K. Furthermore, the FIR calculated from the TDPL spectra obtained during heating and cooling processes, along with repeatability cycles, confirmed the reliability and repeatability of the temperature sensor.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112985"},"PeriodicalIF":2.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-23DOI: 10.1016/j.chemphys.2025.112982
Zhaopeng Zhou , Anqi Jiang
The rapid advancement of artificial intelligence and big data has led to a significant increase in global demand for data storage and information transmission, raising concerns regarding capacity and efficiency. Consequently, the development of novel stimulus-responsive materials has emerged as a critical area of research. This study presents the construction of a new Arsenene/SnSeS heterojunction and employs first-principles methods to manipulate its electronic and optical properties through the application of strain. The computational findings reveal that the Arsenene/SnSeS heterojunction demonstrates remarkable stability and favorable electronic characteristics. Notably, the bandgap of the heterojunction is smaller than that of both the Arsenene monolayer and the SnSeS monolayer, thereby facilitating enhanced charge transfer. Furthermore, the electronic properties of the Arsenene/SnSeS heterojunction can be effectively modulated by strain, which induces redshift or blueshift in the optical absorption peaks. These research outcomes offer valuable insights for the advancement of intelligent stimulus-responsive materials.
{"title":"Research on strain-responsive Arsenene/SnSeS heterojunction for digital media technology: A first-principles calculations","authors":"Zhaopeng Zhou , Anqi Jiang","doi":"10.1016/j.chemphys.2025.112982","DOIUrl":"10.1016/j.chemphys.2025.112982","url":null,"abstract":"<div><div>The rapid advancement of artificial intelligence and big data has led to a significant increase in global demand for data storage and information transmission, raising concerns regarding capacity and efficiency. Consequently, the development of novel stimulus-responsive materials has emerged as a critical area of research. This study presents the construction of a new Arsenene/SnSeS heterojunction and employs first-principles methods to manipulate its electronic and optical properties through the application of strain. The computational findings reveal that the Arsenene/SnSeS heterojunction demonstrates remarkable stability and favorable electronic characteristics. Notably, the bandgap of the heterojunction is smaller than that of both the Arsenene monolayer and the SnSeS monolayer, thereby facilitating enhanced charge transfer. Furthermore, the electronic properties of the Arsenene/SnSeS heterojunction can be effectively modulated by strain, which induces redshift or blueshift in the optical absorption peaks. These research outcomes offer valuable insights for the advancement of intelligent stimulus-responsive materials.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112982"},"PeriodicalIF":2.4,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-21DOI: 10.1016/j.chemphys.2025.112973
Jack P. Schmittdiel , Luis A. Rivera-Rivera , Jay R. Walton
Canonical approaches are applied to generate potentials and forces for interatomic interactions from ab initio data. The methodology has the advantage of generating highly accurate potentials and forces with a minimum number of ab initio points and without the need to fit or interpolate the data. In addition, forces are calculated directly from the ab initio points without the need to take the derivative of the potential. This is a significant advantage since there is no guarantee that the derivative of a function that represents the potential will represent the force curve accurately. The methodology is applied to the Ar-Ar and C2H6-Ar systems. Pair potentials and forces generated by canonical approaches are highly accurate and suitable for molecular dynamics simulations under extreme conditions of high temperature and pressure. In addition, canonical approaches accurately reproduce the attractive tail of interatomic potentials, which is very important in the field of ultracold chemistry.
{"title":"Canonical force fields for interatomic interactions","authors":"Jack P. Schmittdiel , Luis A. Rivera-Rivera , Jay R. Walton","doi":"10.1016/j.chemphys.2025.112973","DOIUrl":"10.1016/j.chemphys.2025.112973","url":null,"abstract":"<div><div>Canonical approaches are applied to generate potentials and forces for interatomic interactions from <em>ab initio</em> data. The methodology has the advantage of generating highly accurate potentials and forces with a minimum number of <em>ab initio</em> points and without the need to fit or interpolate the data. In addition, forces are calculated directly from the <em>ab initio</em> points without the need to take the derivative of the potential. This is a significant advantage since there is no guarantee that the derivative of a function that represents the potential will represent the force curve accurately. The methodology is applied to the Ar-Ar and C<sub>2</sub>H<sub>6</sub>-Ar systems. Pair potentials and forces generated by canonical approaches are highly accurate and suitable for molecular dynamics simulations under extreme conditions of high temperature and pressure. In addition, canonical approaches accurately reproduce the attractive tail of interatomic potentials, which is very important in the field of ultracold chemistry.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112973"},"PeriodicalIF":2.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-21DOI: 10.1016/j.chemphys.2025.112980
Yousif Hussein Azeez , Nzar Rauf Abdullah
This study offers the first comprehensive investigation of the structural, electronic, thermal, and optical characteristics of the mixed metal fluoride AlTlF by density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The negative formation energy of - for AlTlF signifies energetic stability, whereas phonon dispersion analysis demonstrates the lack of negative frequencies, thereby affirming its dynamic stability. Furthermore, the AIMD simulation confirms its thermal stability. Electronic structure simulations reveal a substantial indirect band gap of 5.42 eV (GGA) and 6.75 eV (HSE06), characterized by flat valence bands predominantly comprised of F- states and narrow conduction bands derived from Tl- orbitals, indicative of a robust ionic insulator. Thermal study demonstrates distinct regimes in heat capacity and entropy, influenced by low-frequency Tl–F vibrations and high-frequency Al–F phonons. The smooth, continuous nature of these curves confirms the absence of phase transitions within the studied temperature range, underscoring the material’s thermodynamic stability. Analysis of optical properties reveals a broad transparency window below 5.92 eV using GGA functional, confirming AlTlF’s potential as a UV-transparent material for protective coatings and optical components. The pronounced anisotropic absorption in the ultraviolet (6-8 eV) and deep-ultraviolet (12-14 eV) regions, particularly the enhanced response for /-polarized light, suggests specific applicability in polarization-sensitive deep-UV optoelectronics. This directional absorption behavior, combined with the material’s thermal stability, enables the design of specialized photodetectors for extreme environment applications.
{"title":"Thermally stable 2D AlTlF4: A combined DFT and AIMD study of structural, electronic, thermal, and optical properties","authors":"Yousif Hussein Azeez , Nzar Rauf Abdullah","doi":"10.1016/j.chemphys.2025.112980","DOIUrl":"10.1016/j.chemphys.2025.112980","url":null,"abstract":"<div><div>This study offers the first comprehensive investigation of the structural, electronic, thermal, and optical characteristics of the mixed metal fluoride AlTlF<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> by density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The negative formation energy of -<span><math><mrow><mn>3</mn><mo>.</mo><mn>11</mn><mspace></mspace><mi>eV</mi></mrow></math></span> for AlTlF<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> signifies energetic stability, whereas phonon dispersion analysis demonstrates the lack of negative frequencies, thereby affirming its dynamic stability. Furthermore, the AIMD simulation confirms its thermal stability. Electronic structure simulations reveal a substantial indirect band gap of 5.42 eV (GGA) and 6.75 eV (HSE06), characterized by flat valence bands predominantly comprised of F-<span><math><mrow><mn>2</mn><mi>p</mi></mrow></math></span> states and narrow conduction bands derived from Tl-<span><math><mrow><mn>6</mn><mi>p</mi></mrow></math></span> orbitals, indicative of a robust ionic insulator. Thermal study demonstrates distinct regimes in heat capacity and entropy, influenced by low-frequency Tl–F vibrations and high-frequency Al–F phonons. The smooth, continuous nature of these curves confirms the absence of phase transitions within the studied temperature range, underscoring the material’s thermodynamic stability. Analysis of optical properties reveals a broad transparency window below 5.92 eV using GGA functional, confirming AlTlF<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>’s potential as a UV-transparent material for protective coatings and optical components. The pronounced anisotropic absorption in the ultraviolet (6-8 eV) and deep-ultraviolet (12-14 eV) regions, particularly the enhanced response for <span><math><mi>y</mi></math></span>/<span><math><mi>z</mi></math></span>-polarized light, suggests specific applicability in polarization-sensitive deep-UV optoelectronics. This directional absorption behavior, combined with the material’s thermal stability, enables the design of specialized photodetectors for extreme environment applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112980"},"PeriodicalIF":2.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-19DOI: 10.1016/j.chemphys.2025.112975
Attaur Rahman , Muhammad Haneef , Bin Amin
This research work investigates the structural, elastic and mechanical, electronic, optical, acoustic, and thermal properties of the cubic, lead-free double perovskites Cs₂KAlCl₆, Cs₂KAlBr₆, and Cs₂KAlI₆. The Full-potential linearized augmented plane wave (FP-LAPW) formulism based on density functional theory (DFT) is employed using WIEN2k simulation code. These perovskites strongly fulfill the Gold-Schmidt tolerance (tG) and octahedral (μo) factor conditions. The negative values of formation enthalpy (Hf) demonstrate their thermodynamic stability. However, the Born’s stability criteria, the elastic and mechanical features, confirms its elastic and mechanical stability. The Cs2KAlCl6 and Cs2KAlBr6 are ductile, while Cs2KAlI6 is brittle, and all the three halide double perovskites exhibit anisotropic behavior, as indicated by their Pugh's & Poisson ratios, Cauchy-pressure and anisotropic factors. The acoustic behaviors of these compounds are explored through sound velocities estimations. Thermal performances are analyzed with Debye & melting temperature, and thermal expansion coefficient. It is evident from the electronic properties, these perovskites are direct band semiconductors having band gap values 4.38, 3.04, and 1.71 eV for Cs2KAlCl6, Cs2KAlBr6 and Cs2KAlI6 respectively. A stepwise tuning of the band gap is observed, driven by the increase in ionic size moving down the halogen group from Cl to Br to I, which gradually reduces the band gap. The threshold values of optical parameters for Cs2KAlCl6/(Cs2KAlBr6 and Cs2KAlI6) start from ultraviolet/(visible light) range and both go on maximum in the ultraviolet region. Hence, offer an open range to be used in optoelectronic and photovoltaic renewable energy applications. Moreover, the alignment of valence and conduction band edge potentials relative to the standard redox potentials of water splitting make these compounds a promising choice for hydrogen production through photocatalysis.
{"title":"Cs2KAlY6 (Y = Cl, Br, I): A lead-free double perovskites for optoelectronic and photocatalytic applications","authors":"Attaur Rahman , Muhammad Haneef , Bin Amin","doi":"10.1016/j.chemphys.2025.112975","DOIUrl":"10.1016/j.chemphys.2025.112975","url":null,"abstract":"<div><div>This research work investigates the structural, elastic and mechanical, electronic, optical, acoustic, and thermal properties of the cubic, lead-free double perovskites Cs₂KAlCl₆, Cs₂KAlBr₆, and Cs₂KAlI₆. The Full-potential linearized augmented plane wave (FP-LAPW) formulism based on density functional theory (DFT) is employed using WIEN2k simulation code. These perovskites strongly fulfill the Gold-Schmidt tolerance (t<sub>G</sub>) and octahedral (μ<sub>o</sub>) factor conditions. The negative values of formation enthalpy (<span><math><mo>∆</mo></math></span>H<sub>f</sub>) demonstrate their thermodynamic stability. However, the Born’s stability criteria, the elastic and mechanical features, confirms its elastic and mechanical stability. The Cs<sub>2</sub>KAlCl<sub>6</sub> and Cs<sub>2</sub>KAlBr<sub>6</sub> are ductile, while Cs<sub>2</sub>KAlI<sub>6</sub> is brittle, and all the three halide double perovskites exhibit anisotropic behavior, as indicated by their Pugh's & Poisson ratios, Cauchy-pressure and anisotropic factors. The acoustic behaviors of these compounds are explored through sound velocities estimations. Thermal performances are analyzed with Debye & melting temperature, and thermal expansion coefficient. It is evident from the electronic properties, these perovskites are direct band semiconductors having band gap values 4.38, 3.04, and 1.71 eV for Cs<sub>2</sub>KAlCl<sub>6</sub>, Cs<sub>2</sub>KAlBr<sub>6</sub> and Cs<sub>2</sub>KAlI<sub>6</sub> respectively. A stepwise tuning of the band gap is observed, driven by the increase in ionic size moving down the halogen group from Cl to Br to I, which gradually reduces the band gap. The threshold values of optical parameters for Cs<sub>2</sub>KAlCl<sub>6</sub>/(Cs<sub>2</sub>KAlBr<sub>6</sub> and Cs<sub>2</sub>KAlI<sub>6</sub>) start from ultraviolet/(visible light) range and both go on maximum in the ultraviolet region. Hence, offer an open range to be used in optoelectronic and photovoltaic renewable energy applications. Moreover, the alignment of valence and conduction band edge potentials relative to the standard redox potentials of water splitting make these compounds a promising choice for hydrogen production through photocatalysis.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112975"},"PeriodicalIF":2.4,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1016/j.chemphys.2025.112976
Murillo H. Queiroz , Tiago V. Alves , Roberto Rivelino
We investigate the thresholds of the cooperative effects in hydrogen-bonded chains formed by thymine with 1 to 6 explicit water molecules. Using Density Functional Theory (DFT), combined with Quantum Theory of Atoms in Molecules (QTAIM) and Time-Dependent DFT (TD-DFT), we analyze the evolution of the electronic density at H-bond critical points (ρ H-bond) and its influence on the excited states. Our results indicate that the cooperative effect is stronger with the first water molecules, followed by weaker contributions beyond four water molecules. TD-DFT calculations reveal corresponding shifts in electronic transitions, linking H-bond topology with spectral changes. These findings contribute to a quantitative understanding of hydration effects in nucleobases, with implications for DNA stability and photochemistry.
{"title":"Cooperative and stabilization effects in hydrogen-bonded chains of microhydrated thymine: a QTAIM and TD-DFT study","authors":"Murillo H. Queiroz , Tiago V. Alves , Roberto Rivelino","doi":"10.1016/j.chemphys.2025.112976","DOIUrl":"10.1016/j.chemphys.2025.112976","url":null,"abstract":"<div><div>We investigate the thresholds of the cooperative effects in hydrogen-bonded chains formed by thymine with 1 to 6 explicit water molecules. Using Density Functional Theory (DFT), combined with Quantum Theory of Atoms in Molecules (QTAIM) and Time-Dependent DFT (TD-DFT), we analyze the evolution of the electronic density at H-bond critical points (ρ H-bond) and its influence on the excited states. Our results indicate that the cooperative effect is stronger with the first water molecules, followed by weaker contributions beyond four water molecules. TD-DFT calculations reveal corresponding shifts in electronic transitions, linking H-bond topology with spectral changes. These findings contribute to a quantitative understanding of hydration effects in nucleobases, with implications for DNA stability and photochemistry.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112976"},"PeriodicalIF":2.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340413","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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