Pub Date : 2025-11-13DOI: 10.1016/j.chemphys.2025.113025
Carlos L. Di Prinzio , Luis N. Gerez , Esteban Druetta , Pastor I. Achával , Guillermo G. Aguirre Varela
The temporal evolution of the width of a scratch on the basal plane (0001) of a pure ice single crystal was analyzed under hydrostatic pressures of 0.1 MPa and 10 MPa. The sample was immersed in ultrapure silicone oil at −5 °C to suppress sublimation. A custom-designed pressurized cell enabled the application of controlled hydrostatic pressure, while time-lapse imaging was conducted using an optical microscope equipped with a digital camera. Images of the scratch were acquired at 30-min intervals over a 24-h period. Quantitative analysis of the scratch profiles was performed using image processing software, allowing for the extraction of the time-dependent broadening of the scratch under the specified hydrostatic pressures. From this, the surface self-diffusion coefficient was determined, providing insight into pressure-dependent surface mass transport mechanisms in ice.
{"title":"Surface self-diffusion of ice under high hydrostatic pressure","authors":"Carlos L. Di Prinzio , Luis N. Gerez , Esteban Druetta , Pastor I. Achával , Guillermo G. Aguirre Varela","doi":"10.1016/j.chemphys.2025.113025","DOIUrl":"10.1016/j.chemphys.2025.113025","url":null,"abstract":"<div><div>The temporal evolution of the width of a scratch on the basal plane (0001) of a pure ice single crystal was analyzed under hydrostatic pressures of 0.1 <em>MPa</em> and 10 <em>MPa</em>. The sample was immersed in ultrapure silicone oil at −5 <em>°C</em> to suppress sublimation. A custom-designed pressurized cell enabled the application of controlled hydrostatic pressure, while time-lapse imaging was conducted using an optical microscope equipped with a digital camera. Images of the scratch were acquired at 30-min intervals over a 24-h period. Quantitative analysis of the scratch profiles was performed using image processing software, allowing for the extraction of the time-dependent broadening of the scratch under the specified hydrostatic pressures. From this, the surface self-diffusion coefficient was determined, providing insight into pressure-dependent surface mass transport mechanisms in ice.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113025"},"PeriodicalIF":2.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576689","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 : 2025-11-13DOI: 10.1016/j.chemphys.2025.113027
Masato Kondoh , Saya Suzuki, Taka-aki Ishibashi
We investigated the interaction of an antimicrobial peptide, gramicidin A (gA), with supported lipid bilayers (SLBs) at a CaF2/water interface using total internal reflection-Raman spectroscopy. The gA-addition and premixed experiments were performed, monitoring the CH stretching and amide I regions. In the gA-addition experiment, gA was introduced into the aqueous phase after SLB preparation, and resulting spectral changes were monitored. In the premixed experiment, SLBs were formed from lipid-gA mixtures and spectra were measured. At low peptide concentrations in the premixed experiment, the gA-derived component after subtracting the SLB contribution resembled the changes observed in the gA-addition experiment, confirming that these signals originate from gA interacting with the SLB. At higher peptide concentrations, the spectra changed significantly, suggesting structural alterations of gA due to peptide–peptide interactions. These behaviors were consistent with previously reported gA spectra in vesicles, supporting the validity of SLBs as a model for peptide–lipid interactions.
我们利用全内反射-拉曼光谱研究了抗菌肽gramicidin A （gA）与负载脂质双分子层（slb）在CaF2/水界面上的相互作用。进行了ga添加和预混实验，监测了CH拉伸和酰胺I区。在添加gA的实验中，在制备SLB后，将gA引入水相，并监测其光谱变化。在预混合实验中，脂质- ga混合物形成了slb，并测量了光谱。在低肽浓度预混实验中，减去SLB贡献后的gA衍生成分与添加gA实验中观察到的变化相似，证实了这些信号来自gA与SLB相互作用。在较高的肽浓度下，光谱发生显著变化，表明由于肽-肽相互作用导致gA的结构改变。这些行为与先前报道的囊泡中的gA光谱一致，支持slb作为肽-脂质相互作用模型的有效性。
{"title":"Raman spectra of gramicidin A in a supported lipid bilayer at the CaF2/water interface","authors":"Masato Kondoh , Saya Suzuki, Taka-aki Ishibashi","doi":"10.1016/j.chemphys.2025.113027","DOIUrl":"10.1016/j.chemphys.2025.113027","url":null,"abstract":"<div><div>We investigated the interaction of an antimicrobial peptide, gramicidin A (gA), with supported lipid bilayers (SLBs) at a CaF<sub>2</sub>/water interface using total internal reflection-Raman spectroscopy. The gA-addition and premixed experiments were performed, monitoring the CH stretching and amide I regions. In the gA-addition experiment, gA was introduced into the aqueous phase after SLB preparation, and resulting spectral changes were monitored. In the premixed experiment, SLBs were formed from lipid-gA mixtures and spectra were measured. At low peptide concentrations in the premixed experiment, the gA-derived component after subtracting the SLB contribution resembled the changes observed in the gA-addition experiment, confirming that these signals originate from gA interacting with the SLB. At higher peptide concentrations, the spectra changed significantly, suggesting structural alterations of gA due to peptide–peptide interactions. These behaviors were consistent with previously reported gA spectra in vesicles, supporting the validity of SLBs as a model for peptide–lipid interactions.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"603 ","pages":"Article 113027"},"PeriodicalIF":2.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571118","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 transformation of NO into NH3 (nitric oxide reduction, NORR) provides a potential solution to mitigate NOx emissions and synthesis NH3. To develop catalysts with high catalytic activity and selectivity is still a great challenge. DFT calculations are employed to conduct a thorough investigation into the potential of DACs with a cage-structure on defective graphene for NORR. The results indicate that NO molecule predominantly adsorb onto the catalyst surface in an N-end mode. The stability of the catalyst is confirmed through AIMD simulations, which verify that both homonuclear and heteronuclear bimetallic structures can sustain stable geometric configurations. Upon analyzing the NORR pathways, the N-end enzymatic pathway is the most favorable for the majority of catalysts. Moreover, the investigated DACs catalysts have higher NH3 selectivity than HER. 2Pt@gra catalyst exhibits the lowest limiting potential (−0.07 V) and can effectively suppress the generation of by-products N2, demonstrating superior catalytic performance.
{"title":"Theoretical study of bimetallic catalysts for NO reduction to ammonia on defective graphene","authors":"Wenlong Guo , Xinlin Tang , Shirui Xiao , Xuanjun Shen , Haiyue Liao , Jia Peng , Xin Lian","doi":"10.1016/j.chemphys.2025.113021","DOIUrl":"10.1016/j.chemphys.2025.113021","url":null,"abstract":"<div><div>The transformation of NO into NH<sub>3</sub> (nitric oxide reduction, NORR) provides a potential solution to mitigate NO<sub>x</sub> emissions and synthesis NH<sub>3</sub>. To develop catalysts with high catalytic activity and selectivity is still a great challenge. DFT calculations are employed to conduct a thorough investigation into the potential of DACs with a cage-structure on defective graphene for NORR. The results indicate that NO molecule predominantly adsorb onto the catalyst surface in an N-end mode. The stability of the catalyst is confirmed through AIMD simulations, which verify that both homonuclear and heteronuclear bimetallic structures can sustain stable geometric configurations. Upon analyzing the NORR pathways, the N-end enzymatic pathway is the most favorable for the majority of catalysts. Moreover, the investigated DACs catalysts have higher NH<sub>3</sub> selectivity than HER. 2Pt@gra catalyst exhibits the lowest limiting potential (−0.07 V) and can effectively suppress the generation of by-products N<sub>2</sub>, demonstrating superior catalytic performance.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113021"},"PeriodicalIF":2.4,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526349","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 density, structures, dynamical properties and hydrogen bond (HB) dynamics of protic [EtNH3][NO3] and aprotic [Emim][NTF2] ionic liquid mixtures forming {[Emim][NTF2]}x{[EtNH3][NO3]}(1-x) with the molar fraction x = 0.00, 0.25, 0.50, 0.75 and 1.00 have been systematically investigated by using molecular dynamics simulations and a series of ab initio calculations. Our simulation results demonstrate that the studied IL mixtures is a quasi-ideal system, where two positive deviations (x = 0.25 and 0.50) and one negative deviation (x = 0.75) of the excess molar volume are less than 0.18 cm3·mol−1. Further analysis indicates that the translational as well as rotational motions of [Emim]+ and [NTF2]− are restricted significantly with the decreasing the molar fractions. However, for [EtNH3]+ and [NO3]−, they display similar restrictions with the increasing the molar fractions in IL mixtures. Such restrictions can be attributed to the enhanced HB dynamics between [EtNH3]+ and [NO3]− in the IL mixtures. Moreover, the HB strength of [Emim]+-[NTF2]− is enhanced with decreasing molar fractions in the IL mixtures, which can be better explained by the slower translational and rotational motions for [Emim]+ and [NTF₂]− ions. More importantly, the binding energies for above cations and anions ion-pairs were determined by the ab initio calculations, which are in accordance with the MD simulation results. Our simulation results provide a molecular-level understanding the structures and dynamics of protic [EtNH3][NO3] and aprotic [Emim][NTF2] ionic liquid mixtures, and will be a bit favorable to design and synthesis IL mixtures with specific properties.
{"title":"Understanding the structures and dynamics of protic [EtNH3][NO3] and aprotic [Emim][NTF₂] ionic liquid mixtures from molecular dynamics simulation","authors":"Wenshu Liang, Dong Wang, Jia-ni Fan, Guangli Zhou, Qiying Xia, Xia Leng, Yunzhi Li","doi":"10.1016/j.chemphys.2025.113020","DOIUrl":"10.1016/j.chemphys.2025.113020","url":null,"abstract":"<div><div>The density, structures, dynamical properties and hydrogen bond (HB) dynamics of protic [EtNH<sub>3</sub>][NO<sub>3</sub>] and aprotic [Emim][NTF<sub>2</sub>] ionic liquid mixtures forming {[Emim][NTF<sub>2</sub>]}<sub>x</sub>{[EtNH<sub>3</sub>][NO<sub>3</sub>]}<sub>(1-x)</sub> with the molar fraction x = 0.00, 0.25, 0.50, 0.75 and 1.00 have been systematically investigated by using molecular dynamics simulations and a series of ab initio calculations. Our simulation results demonstrate that the studied IL mixtures is a quasi-ideal system, where two positive deviations (x = 0.25 and 0.50) and one negative deviation (x = 0.75) of the excess molar volume are less than 0.18 cm<sup>3</sup>·mol<sup>−1</sup>. Further analysis indicates that the translational as well as rotational motions of [Emim]<sup>+</sup> and [NTF<sub>2</sub>]<sup>−</sup> are restricted significantly with the decreasing the molar fractions. However, for [EtNH<sub>3</sub>]<sup>+</sup> and [NO<sub>3</sub>]<sup>−</sup>, they display similar restrictions with the increasing the molar fractions in IL mixtures. Such restrictions can be attributed to the enhanced HB dynamics between [EtNH<sub>3</sub>]<sup>+</sup> and [NO<sub>3</sub>]<sup>−</sup> in the IL mixtures. Moreover, the HB strength of [Emim]<sup>+</sup>-[NTF<sub>2</sub>]<sup>−</sup> is enhanced with decreasing molar fractions in the IL mixtures, which can be better explained by the slower translational and rotational motions for [Emim]<sup>+</sup> and [NTF₂]<sup>−</sup> ions. More importantly, the binding energies for above cations and anions ion-pairs were determined by the ab initio calculations, which are in accordance with the MD simulation results. Our simulation results provide a molecular-level understanding the structures and dynamics of protic [EtNH<sub>3</sub>][NO<sub>3</sub>] and aprotic [Emim][NTF<sub>2</sub>] ionic liquid mixtures, and will be a bit favorable to design and synthesis IL mixtures with specific properties.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113020"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526350","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}
NiTe nanorods with varying levels of Molybdenum substitution were grown by a facile hydrothermal process, and their performance as electrocatalysts for hydrogen evolution reaction (HER) was evaluated. The 5% Mo-substituted NiTe was found to have the best performance as HER electrocatalyst with the lowest overpotential among pristine and substituted NiTe. Density functional theory studies further corroborate our experimental findings, showing that an optimum substitution of Mo in NiTe enhances the electrocatalytic property of NiTe. Our findings shed light on the factors determining the optimum substitution levels in electrocatalysts based on transition metal dichalcogenides.
{"title":"Enhanced electrocatalytic activity of optimally Mo-substituted NiTe2 nanorods for hydrogen evolution","authors":"Joyal Sunny , Karuna Sharma , Poonam Moar , Imtiaz Ahmed , Krishna Kanta Haldar , Krishnakanta Mondal , Sourabh Barua","doi":"10.1016/j.chemphys.2025.113018","DOIUrl":"10.1016/j.chemphys.2025.113018","url":null,"abstract":"<div><div>NiTe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> nanorods with varying levels of Molybdenum substitution were grown by a facile hydrothermal process, and their performance as electrocatalysts for hydrogen evolution reaction (HER) was evaluated. The 5% Mo-substituted NiTe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> was found to have the best performance as HER electrocatalyst with the lowest overpotential among pristine and substituted NiTe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. Density functional theory studies further corroborate our experimental findings, showing that an optimum substitution of Mo in NiTe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> enhances the electrocatalytic property of NiTe<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>. Our findings shed light on the factors determining the optimum substitution levels in electrocatalysts based on transition metal dichalcogenides.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113018"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576680","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 : 2025-11-10DOI: 10.1016/j.chemphys.2025.113019
K.L. Ngai , Yanhui Zhang , Li-Min Wang , S. Capaccioli
In many studies of the dynamics of glass-forming materials pressure P and temperature T were varied while keeping the structural α-relaxation time τα(T,P) constant. Found generally by experiments and simulations is the frequency dispersion of the α-relaxation, or the exponent βK of its Kohlrausch-Williams-Watts correlation function, remains the same. Moreover, the Johari-Goldstein (JG) β-relaxation time τβ(T,P) is also constant. This remarkable and ubiquitous property of invariance of τα(T,P), βK(T,P), and τβ(T,P) collectively to varying P and T at constant τα(T,P) originates from the inseparable connection between the JGβ relaxation and the α-relaxation as predicted by the Coupling Model. Not considered before in this property is the caged dynamics, which has all molecules confined within cages via the intermolecular potential, and it is the precursor of the JGβ relaxation. The caged dynamics is strongly coupled to the JGβ and α relaxations as indicated by its decay and eventual termination by the onset of the JGβ relaxation, and its change of temperature dependence on crossing the glass transition temperatures Tgβ and Tgα of the JGβ and α relaxations. The strong connections of the caged dynamics to the JGβ and α relaxations suggest it is also invariant to changes of P and T at constant τα(T,P). Collected in this paper are data of caged dynamics from neutron scattering and dielectric relaxation experiments, and molecular dynamics simulations performed at different combinations of P and T at constant τα(T,P). The results clearly verify the invariance of the caged dynamics collectively with τα(T,P), βK(T,P), and τβ(T,P) to variations of P and T at constant τα(T,P). This co-invariance property extended to include the caged dynamics is expected to have repercussion on current research of the dynamics and thermodynamics of glass-forming materials.
{"title":"Co-invariance of caged dynamics with α and β relaxation to variation of temperature and pressure with the α-relaxation time kept constant","authors":"K.L. Ngai , Yanhui Zhang , Li-Min Wang , S. Capaccioli","doi":"10.1016/j.chemphys.2025.113019","DOIUrl":"10.1016/j.chemphys.2025.113019","url":null,"abstract":"<div><div>In many studies of the dynamics of glass-forming materials pressure <em>P</em> and temperature <em>T</em> were varied while keeping the structural α-relaxation time <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>) constant. Found generally by experiments and simulations is the frequency dispersion of the α-relaxation, or the exponent <em>β</em><sub><em>K</em></sub> of its Kohlrausch-Williams-Watts correlation function, remains the same. Moreover, the Johari-Goldstein (JG) <em>β</em>-relaxation time <em>τ</em><sub><em>β</em></sub>(<em>T,P</em>) is also constant. This remarkable and ubiquitous property of invariance of <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>), <em>β</em><sub><em>K</em></sub>(<em>T,P</em>), and <em>τ</em><sub><em>β</em></sub>(<em>T,P</em>) collectively to varying <em>P</em> and <em>T</em> at constant <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>) originates from the inseparable connection between the JG<em>β</em> relaxation and the α-relaxation as predicted by the Coupling Model. Not considered before in this property is the caged dynamics, which has all molecules confined within cages via the intermolecular potential, and it is the precursor of the JG<em>β</em> relaxation. The caged dynamics is strongly coupled to the JGβ and α relaxations as indicated by its decay and eventual termination by the onset of the JGβ relaxation, and its change of temperature dependence on crossing the glass transition temperatures <em>T</em><sub><em>gβ</em></sub> and <em>T</em><sub><em>gα</em></sub> of the JGβ and α relaxations. The strong connections of the caged dynamics to the JGβ and α relaxations suggest it is also invariant to changes of <em>P</em> and <em>T</em> at constant <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>). Collected in this paper are data of caged dynamics from neutron scattering and dielectric relaxation experiments, and molecular dynamics simulations performed at different combinations of <em>P</em> and <em>T</em> at constant <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>). The results clearly verify the invariance of the caged dynamics collectively with <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>), <em>β</em><sub><em>K</em></sub>(<em>T,P</em>), and <em>τ</em><sub><em>β</em></sub>(<em>T,P</em>) to variations of <em>P</em> and <em>T</em> at constant <em>τ</em><sub><em>α</em></sub>(<em>T,P</em>). This co-invariance property extended to include the caged dynamics is expected to have repercussion on current research of the dynamics and thermodynamics of glass-forming materials.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113019"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526351","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 : 2025-11-10DOI: 10.1016/j.chemphys.2025.113024
Pallavi D. Hambarde, Nitin P. Garad, Ashok C. Kumbharkhane
•
Investigated the dielectric properties and molecular interactions of isopropyl acetate (IPAc) and isoamyl acetate (IAA) with dimethyl sulfoxide (DMSO) binary mixtures using Time Domain Reflectometry (TDR) over 10 MHz–30 GHz.
•
Determined static dielectric constant (ε₀) and relaxation time (τ) by fitting complex permittivity spectra to the Cole–Davidson model with least squares fitting.
•
Evaluated molecular interactions and dielectric relaxation through Bruggeman factor, Kirkwood correlation factor, excess permittivity, and thermodynamic parameters.
•
Revealed structural differences and molecular interactions influenced by chain length and concentration, providing insights into dipole orientation and mixture behavior.
{"title":"Dielectric characterization and thermodynamic analysis of iso-propyl acetate and Iso-amyl acetate with dimethyl sulphoxide binary mixtures using time domain reflectometry","authors":"Pallavi D. Hambarde, Nitin P. Garad, Ashok C. Kumbharkhane","doi":"10.1016/j.chemphys.2025.113024","DOIUrl":"10.1016/j.chemphys.2025.113024","url":null,"abstract":"<div><div><ul><li><span>•</span><span><div>Investigated the dielectric properties and molecular interactions of isopropyl acetate (IPAc) and isoamyl acetate (IAA) with dimethyl sulfoxide (DMSO) binary mixtures using Time Domain Reflectometry (TDR) over 10 MHz–30 GHz.</div></span></li><li><span>•</span><span><div>Determined static dielectric constant (ε₀) and relaxation time (τ) by fitting complex permittivity spectra to the Cole–Davidson model with least squares fitting.</div></span></li><li><span>•</span><span><div>Evaluated molecular interactions and dielectric relaxation through Bruggeman factor, Kirkwood correlation factor, excess permittivity, and thermodynamic parameters.</div></span></li><li><span>•</span><span><div>Revealed structural differences and molecular interactions influenced by chain length and concentration, providing insights into dipole orientation and mixture behavior.</div></span></li></ul></div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113024"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526392","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 : 2025-11-08DOI: 10.1016/j.chemphys.2025.113017
Leif Holmlid , Linnéa Gunnarsson
We show that micro-Raman spectroscopy is useful for studying hydrogen Rydberg Matter of the type H(l) at the generating catalyst surface. The excited hydrogen atoms comprising the H(RM) materials are observed in the anti-Stokes range, in the same way as the excited potassium atoms in potassium Rydberg Matter K(RM) were previously observed (Alpermann and Holmlid 2007). Atomic hydrogen transitions are observed at 320 K. This gives strong evidence for the formation of Rydberg Matter of atomic hydrogen on the potassium containing catalyst. Adsorbed hydrogen H2 molecules and other hydrogen containing molecules are observed in the Stokes range at shifts up to 4239 cm−1.
结果表明，微拉曼光谱可用于研究催化剂表面H(l)型氢里德堡物质。组成H（RM）材料的受激氢原子在反斯托克斯范围内被观察到，就像以前观察到的Rydberg物质K（RM）中的受激钾原子一样（Alpermann and Holmlid 2007）。在320 K时观察到原子氢跃迁。这为在含钾催化剂上形成氢原子里德伯物质提供了强有力的证据。吸附的H2分子和其他含氢分子在Stokes范围内的位移高达4239 cm−1。
{"title":"Micro-Raman study of H(l) precursor states of ultra-dense hydrogen H(0)","authors":"Leif Holmlid , Linnéa Gunnarsson","doi":"10.1016/j.chemphys.2025.113017","DOIUrl":"10.1016/j.chemphys.2025.113017","url":null,"abstract":"<div><div>We show that micro-Raman spectroscopy is useful for studying hydrogen Rydberg Matter of the type H(<em>l</em>) at the generating catalyst surface. The excited hydrogen atoms comprising the H(RM) materials are observed in the anti-Stokes range, in the same way as the excited potassium atoms in potassium Rydberg Matter K(RM) were previously observed (Alpermann and Holmlid 2007). Atomic hydrogen transitions are observed at 320 K. This gives strong evidence for the formation of Rydberg Matter of atomic hydrogen on the potassium containing catalyst. Adsorbed hydrogen H<sub>2</sub> molecules and other hydrogen containing molecules are observed in the Stokes range at shifts up to 4239 cm<sup>−1</sup>.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113017"},"PeriodicalIF":2.4,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576681","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 : 2025-11-07DOI: 10.1016/j.chemphys.2025.113015
Mohamed El Amine El Goutni , Hela Ferjani , Mohammed Batouche , Taieb Seddik
Vacancy-ordered double perovskites A₂TeX₆ (A = Cs, Rb; X = Cl, Br, I) are promising lead-free semiconductors for photocatalysis and photovoltaics. Using density functional theory (DFT) combined with experimental comparisons, we investigated their structural, electronic, and optical properties. Phonon dispersions and ab initio molecular dynamics (AIMD) simulations at 300 K confirm their dynamical stability, with energy fluctuations <0.1 eV and temperature oscillations within ±30 K. Calculated indirect band gaps range from 1.40 eV (Cs₂TeI₆) to 2.65 eV (Rb₂TeCl₆), in excellent agreement with reported experimental values (1.5–2.7 eV). Effective carrier masses are light (0.23–0.41 mₑ), supporting mobility ratios exceeding 102, favorable for charge transport. Density of states analysis indicates Te-p states dominate the valence band, while halide-p orbitals shape the conduction band. Optical spectra confirm strong absorption in the visible region, while band edge alignment indicates suitability for water oxidation and CO₂ reduction. These results demonstrate A₂TeX₆ compounds as stable, tunable, and environmentally benign candidates for next-generation energy conversion devices.
空位有序双钙钛矿A₂TeX₆（A = Cs, Rb; X = Cl, Br， I）是一种很有前途的用于光催化和光伏发电的无铅半导体材料。利用密度泛函理论（DFT）结合实验比较，研究了它们的结构、电子和光学性质。300 K下声子色散和从头算分子动力学（AIMD）模拟证实了它们的动力学稳定性，能量波动<；0.1 eV，温度振荡在±30 K内。计算的间接带隙范围从1.40 eV （Cs₂TeI₆）到2.65 eV （Rb₂TeCl₆），与报告的实验值（1.5-2.7 eV）非常吻合。有效载流子质量较轻（0.23-0.41 mₑ），迁移率超过102，有利于电荷输运。态密度分析表明Te-p态主导价带，而卤化物-p轨道主导导带。光谱证实了可见光区的强吸收，而带边缘排列表明适合水氧化和CO₂还原。这些结果证明了A₂TeX₆化合物是下一代能量转换装置的稳定、可调和环保的候选物。
{"title":"Tailoring solar photocatalysis and water oxidation in lead-free A₂TeX₆ (A = Cs, Rb; X = Cl, Br, I) perovskites via halide substitution","authors":"Mohamed El Amine El Goutni , Hela Ferjani , Mohammed Batouche , Taieb Seddik","doi":"10.1016/j.chemphys.2025.113015","DOIUrl":"10.1016/j.chemphys.2025.113015","url":null,"abstract":"<div><div>Vacancy-ordered double perovskites A₂TeX₆ (A = Cs, Rb; X = Cl, Br, I) are promising lead-free semiconductors for photocatalysis and photovoltaics. Using density functional theory (DFT) combined with experimental comparisons, we investigated their structural, electronic, and optical properties. Phonon dispersions and ab initio molecular dynamics (AIMD) simulations at 300 K confirm their dynamical stability, with energy fluctuations <0.1 eV and temperature oscillations within ±30 K. Calculated indirect band gaps range from 1.40 eV (Cs₂TeI₆) to 2.65 eV (Rb₂TeCl₆), in excellent agreement with reported experimental values (1.5–2.7 eV). Effective carrier masses are light (0.23–0.41 mₑ), supporting mobility ratios exceeding 10<sup>2</sup>, favorable for charge transport. Density of states analysis indicates Te-p states dominate the valence band, while halide-p orbitals shape the conduction band. Optical spectra confirm strong absorption in the visible region, while band edge alignment indicates suitability for water oxidation and CO₂ reduction. These results demonstrate A₂TeX₆ compounds as stable, tunable, and environmentally benign candidates for next-generation energy conversion devices.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113015"},"PeriodicalIF":2.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526390","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 : 2025-11-06DOI: 10.1016/j.chemphys.2025.112967
Wahidullah Khan , M. Kashif Masood , Shumaila Bibi , Irslan Ullah Ashraf , M.S. Akbar , F. Tawfiq
Aluminum-based hydrides are promising candidates for hydrogen storage due to their lightweight nature, cost-effectiveness, high hydrogen density, and favorable kinetics, aligning well with the US DOE on-board storage targets. In this study, the structural, electronic, optical, and hydrogen storage properties of AeAlH3 (Ae = Li, Ca, Sr, Ba) were systematically investigated using first-principles calculations within the GGA-PBE framework. Simulated X-ray diffraction patterns confirmed that all compounds are cubic polycrystalline phases. The calculated gravimetric hydrogen storage capacities were 8.18, 4.31, 2.25, and 1.81 wt% for LiAlH3, CaAlH3, SrAlH3, and BaAlH3, respectively, and their formation energies verified thermodynamically stability. Optical analysis, including conductivity, absorption coefficients, and reflectance, suggests potential applications in optoelectronics, with SrAlH3 exhibiting the highest static dielectric function. AIMD simulation at room temperature confirmed structural robustness without appreciable distortion. Electronic structure calculations revealed metallic characteristics, dominated by H-1s and Al-3p orbital contributions, while Hirshfeld and Mulliken charge analysis indicated charge transfer from Ae and Al atoms to hydrogen. These findings provide valuable insights into the Al-based perovskite hydrides and highlight their potential as efficient hydrogen storage materials for future energy storage applications.
铝基氢化物由于其轻量化、高成本效益、高氢密度和良好的动力学特性，与美国能源部的车载存储目标很好地吻合，是储氢的有希望的候选者。在本研究中，采用GGA-PBE框架下的第一性原理计算，系统地研究了AeAlH3 （Ae = Li, Ca, Sr, Ba）的结构、电子、光学和储氢性能。模拟x射线衍射图证实所有化合物均为立方多晶相。计算得到LiAlH3、CaAlH3、SrAlH3和BaAlH3的重量储氢容量分别为8.18%、4.31%、2.25%和1.81 wt%，其形成能验证了它们的热力学稳定性。光学分析，包括电导率、吸收系数和反射率，表明了在光电子学中的潜在应用，其中SrAlH3表现出最高的静态介电函数。室温下的AIMD模拟证实了结构的稳健性，没有明显的变形。电子结构计算显示了金属特征，主要是H-1s和Al-3p轨道的贡献，而Hirshfeld和Mulliken的电荷分析表明了Ae和Al原子向氢原子的电荷转移。这些发现为铝基钙钛矿氢化物提供了有价值的见解，并突出了它们作为未来储能应用的高效储氢材料的潜力。
{"title":"First principles and molecular dynamics insights into thermally stable aluminum-based perovskite hydrides for hydrogen storage applications","authors":"Wahidullah Khan , M. Kashif Masood , Shumaila Bibi , Irslan Ullah Ashraf , M.S. Akbar , F. Tawfiq","doi":"10.1016/j.chemphys.2025.112967","DOIUrl":"10.1016/j.chemphys.2025.112967","url":null,"abstract":"<div><div>Aluminum-based hydrides are promising candidates for hydrogen storage due to their lightweight nature, cost-effectiveness, high hydrogen density, and favorable kinetics, aligning well with the US DOE on-board storage targets. In this study, the structural, electronic, optical, and hydrogen storage properties of <em>Ae</em>AlH<sub>3</sub> (<em>Ae</em> = Li, Ca, Sr, Ba) were systematically investigated using first-principles calculations within the GGA-PBE framework. Simulated X-ray diffraction patterns confirmed that all compounds are cubic polycrystalline phases. The calculated gravimetric hydrogen storage capacities were 8.18, 4.31, 2.25, and 1.81 wt% for LiAlH<sub>3</sub>, CaAlH<sub>3</sub>, SrAlH<sub>3</sub>, and BaAlH<sub>3</sub>, respectively, and their formation energies verified thermodynamically stability. Optical analysis, including conductivity, absorption coefficients, and reflectance, suggests potential applications in optoelectronics, with SrAlH<sub>3</sub> exhibiting the highest static dielectric function. AIMD simulation at room temperature confirmed structural robustness without appreciable distortion. Electronic structure calculations revealed metallic characteristics, dominated by H-1s and Al-3p orbital contributions, while Hirshfeld and Mulliken charge analysis indicated charge transfer from Ae and Al atoms to hydrogen. These findings provide valuable insights into the Al-based perovskite hydrides and highlight their potential as efficient hydrogen storage materials for future energy storage applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112967"},"PeriodicalIF":2.4,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526394","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号