Journal of Chemical Physics最新文献_第5页

Interplay of ethaline and water dynamics in a hydrated eutectic solvent: Deuteron and oxygen magnetic resonance studies of aqueous ethaline. 在水合共晶溶剂中，乙烷和水动力学的相互作用：水乙烷的氘核和氧磁共振研究。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0244255

Yannik Hinz, Roland Böhmer

{"title":"Interplay of ethaline and water dynamics in a hydrated eutectic solvent: Deuteron and oxygen magnetic resonance studies of aqueous ethaline.","authors":"Yannik Hinz, Roland Böhmer","doi":"10.1063/5.0244255","DOIUrl":"https://doi.org/10.1063/5.0244255","url":null,"abstract":"For many technological processes, the impact of water addition on the properties of deep eutectic solvents is of central importance. In this context, the impact of hydration on the reorientational dynamics of the deep eutectic solvent (DES) ethaline, a 2:1 molar mixture of ethylene glycol and choline chloride, was studied. Its overall response was explored by means of shear mechanical rheology. To achieve component-selective insights into the dynamics of this material, isotope-edited deuteron and oxygen spin-lattice and spin-spin relaxometry, as well as stimulated-echo spectroscopy, were applied and yielded motional correlation times from above room temperature down to the highly viscous regime. For all temperatures, the cholinium anion was found to reorient about two times slower than ethylene glycol, while the water and the ethylene glycol molecules display very similar mobilities. While hydration enhances the component dynamics with respect to that of dry ethaline, the present findings reveal that it does not detectably increase the heterogeneity of the solvent. Merely, the time scale similarity that is found for the hydrogen bond donor and the water molecules over a particularly wide temperature range impressively attests to the stability of the native solvent structure in the \"water-in-DES\" regime.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 23","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142854431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of H2O and CO2 on CO oxidation over Pt/SSZ-13 with active sites regulated by Lewis acidity. H2O和CO2对活性位点受Lewis酸度调控的Pt/SSZ-13上CO氧化的影响

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0242302

Yunhe Li, Yanming Ma, Yilin Wei, Peiyuan Liang, Yixuan Yu, Wei Pei, Tianjun Sun

{"title":"Effect of H2O and CO2 on CO oxidation over Pt/SSZ-13 with active sites regulated by Lewis acidity.","authors":"Yunhe Li, Yanming Ma, Yilin Wei, Peiyuan Liang, Yixuan Yu, Wei Pei, Tianjun Sun","doi":"10.1063/5.0242302","DOIUrl":"https://doi.org/10.1063/5.0242302","url":null,"abstract":"Strategies for controlling the size of metal species using zeolites and their catalytic behavior in industrially relevant processes have attracted widespread attention, but the effect of H2O and CO2 on the catalytic performance of zeolite-based metal catalysts remains obscure. This study investigated the influence of H2O and CO2 on CO oxidation over zeolite-based metal catalysts, along with the precise control of active sites through the regulation of Lewis acidity. It was found that the presence of H2O enhanced CO oxidation and alleviated the inhibitory effect of CO2. Abundant Lewis acid sites of low SiO2/Al2O3 ratios in the Pt/SSZ-13 catalyst facilitate Pt dispersion (61.07%), a high Ptn+/Pt ratio (4.43), and small Pt particles (2.31 nm) formation. In situ DRIFTS revealed that CO2 inhibits CO adsorption and the decomposition of carbon intermediates. Water alters the CO adsorption configuration of Pt0, thereby weakening the Pt-CO bond to promote the CO oxidation reaction. Meanwhile, water dissociated into hydroxyl groups on the surface adsorbs oxygen species, participating in reactions and promoting CO2 production from carbon intermediates. H218O isotope labeling experiments validated the water involvement in the reaction and emphasized the importance of the presence of oxygen species during the water dissociation process. Regulation of Lewis acid sites promotes the Ptn+ species formation, enhancing the CO oxidation activity, while Pt0 species enhance the water-promotion effect.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 23","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142864339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The impact of Helicobacter pylori on gastric cancer formation and early warning signal identification. 幽门螺杆菌对胃癌形成及预警信号识别的影响。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0243016

Chong Yu, Jin Wang

{"title":"The impact of Helicobacter pylori on gastric cancer formation and early warning signal identification.","authors":"Chong Yu, Jin Wang","doi":"10.1063/5.0243016","DOIUrl":"https://doi.org/10.1063/5.0243016","url":null,"abstract":"Gastric cancer is highly prevalent in Asia and is characterized by poor prognosis post-surgery and a high recurrence rate within five years. Research has highlighted the role of Helicobacter pylori in initiating or accelerating gastric cancer development. However, quantitative analysis of its impact on gastric cancer carcinogenesis is still lacking. This study employs gene regulatory networks and landscape and flux theory, integrating genetic and epigenetic factors, to quantitatively elucidate how Helicobacter pylori influences gastric cancer progression. Varied Helicobacter pylori infection concentrations lead to significant shifts in system thermodynamic and dynamic driving forces, altering gene expression levels. Quantitative analysis of entropy production rate and mean-flux in the gastric cancer system reveals the global changes in thermodynamic and dynamic driving forces. Coupled with autocorrelation, cross correlation, and variance analysis, we pinpoint critical stages of Helicobacter pylori infection, serving as early warning signals for gastric cancer. This approach bridges theoretical and clinical realms, dynamically assessing Helicobacter pylori's impact on gastric cancer and identifying crucial early warning signals, with significant clinical and translational implications.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 23","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142864345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nuclear quantum effects on glassy water under pressure: Vitrification and pressure-induced transformations. 压力下玻璃水的核量子效应：玻璃化和压力诱导的转化。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0238823

Ali Eltareb, Bibi A Khan, Gustavo E Lopez, Nicolas Giovambattista

{"title":"Nuclear quantum effects on glassy water under pressure: Vitrification and pressure-induced transformations.","authors":"Ali Eltareb, Bibi A Khan, Gustavo E Lopez, Nicolas Giovambattista","doi":"10.1063/5.0238823","DOIUrl":"10.1063/5.0238823","url":null,"abstract":"We perform classical molecular dynamics (MD) and path-integral MD (PIMD) simulations of H2O and D2O using the q-TIP4P/F model over a wide range of temperatures and pressures to study the nuclear quantum effects (NQEs) on (i) the vitrification of liquid water upon isobaric cooling at different pressures and (ii) pressure-induced transformations at constant temperature between low-density amorphous and high-density amorphous ice (LDA and HDA) and hexagonal ice Ih and HDA. Upon isobaric cooling, classical and quantum H2O and D2O vitrify into a continuum of intermediate amorphous ices (IA), with densities in-between those of LDA and HDA (depending on pressure). Importantly, the density of the IA varies considerably if NQEs are included (similar conclusions hold for ice Ih at all pressures studied). While the structure of the IA is not very sensitive to NQE, the geometry of the hydrogen-bond (HB) is. NQE leads to longer and less linear HB in LDA, HDA, and ice Ih than found in the classical case. Interestingly, the delocalization of the H/D atoms is non-negligible and identical in LDA, HDA, and ice Ih at all pressures studied. Our isothermal compression/decompression MD/PIMD simulations show that classical and quantum H2O and D2O all exhibit LDA-HDA and ice Ih-HDA transformations, consistent with experiments. The inclusion of NQE leads to a softer HB-network, which lowers slightly the LDA/ice Ih-to-HDA transformation pressures. Interestingly, the HB in HDA is longer and less linear than in LDA, which is counterintuitive given that HDA is ≈25% denser than LDA. Overall, our results show that, while classical computer simulations provide the correct qualitative phenomenology of ice and glassy water, NQEs are necessary for a quantitative description.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 23","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11651710/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A semiclassical non-adiabatic phase-space approach to molecular translations and rotations: Surface hopping with electronic inertial effects. 分子平移和旋转的半经典非绝热相空间方法：具有电子惯性效应的表面跳变。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0242673

Xuezhi Bian, Yanze Wu, Tian Qiu, Zhen Tao, Joseph E Subotnik

引用次数: 0

Bending elasticity of the reversible freely jointed chain. 可逆自由连接链的弯曲弹性。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-21 DOI: 10.1063/5.0246283

Minsu Yi, Dongju Lee, Panayotis Benetatos

{"title":"Bending elasticity of the reversible freely jointed chain.","authors":"Minsu Yi, Dongju Lee, Panayotis Benetatos","doi":"10.1063/5.0246283","DOIUrl":"https://doi.org/10.1063/5.0246283","url":null,"abstract":"The freely jointed chain model with reversible hinges (rFJC) is the simplest theoretical model, which captures reversible transitions of the local bending stiffness along the polymer chain backbone (e.g., helix-coil-type of local conformational changes or changes due to the binding/unbinding of ligands). In this work, we analyze the bending fluctuations and the bending response of a grafted rFJC in the Gibbs (fixed-force) ensemble. We obtain a recursion relation for the partition function of the grafted rFJC under a bending force, which allows, in principle, an exact-numerical calculation of the behavior of an rFJC of arbitrary size. In contrast to stretching, we show that under sufficiently stiff conditions, the differential bending compliance and the mean fraction of closed hinges are non-monotonic functions of the force. We also obtain the persistence length Lp of the rFJC and the moments ⟨R2⟩ (mean-square end-to-end distance) and ⟨z2⟩ (mean-square transverse deflection) for the discrete chain and take the continuum limit. The tangent vector auto-correlation decays exponentially, as in the wormlike chain model (WLC). Remarkably, the expression of ⟨R2⟩ as a function of the contour length L becomes the same as that in the WLC. In the thermodynamic limit, we have calculated the exact bending response analytically. As expected, for L ≫ Lp, the boundary conditions do not matter, and the bending becomes equivalent to stretching. In contrast, for Lp ≫ L, we have shown the non-monotonicity of the bending response (the compliance and mean fraction of closed hinges).","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 23","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142854335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanical and thermodynamic routes to the liquid-liquid interfacial tension and mixing free energy by molecular dynamics. 用分子动力学研究液-液界面张力和混合自由能的力学和热力学途径。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-14 DOI: 10.1063/5.0238862

Rei Ogawa, Hiroki Kusudo, Takeshi Omori, Edward R Smith, Laurent Joly, Samy Merabia, Yasutaka Yamaguchi

{"title":"Mechanical and thermodynamic routes to the liquid-liquid interfacial tension and mixing free energy by molecular dynamics.","authors":"Rei Ogawa, Hiroki Kusudo, Takeshi Omori, Edward R Smith, Laurent Joly, Samy Merabia, Yasutaka Yamaguchi","doi":"10.1063/5.0238862","DOIUrl":"https://doi.org/10.1063/5.0238862","url":null,"abstract":"In this study, we carried out equilibrium molecular dynamics (EMD) simulations of the liquid-liquid (LL) interface between two different Lennard-Jones components with varying miscibility, where we examined the relation between the interfacial tension and the free energy to completely isolate the two liquids using both a mechanical and thermodynamic approach. Using the mechanical approach, we obtained a stress distribution around a quasi-one-dimensional EMD system with a flat LL interface. From the stress distribution, we calculated the LL interfacial tension based on Bakker's equation, which uses the stress anisotropy around the interface, and measured how it varied with miscibility. The second approach uses thermodynamic integration by enforcing quasi-static isolation of the two liquids to calculate the free energy. This uses the same EMD systems as the mechanical approach, with both extended dry-surface and phantom-wall (PW) schemes applied. When the two components were immiscible, the mechanical interfacial tension and isolation free energy were in good agreement. When the components were miscible, the values were significantly different. From the result of PW for the case of completely mixed liquids, the difference was attributed to the additional free energy required to separate the binary mixture into single components against the osmotic pressure prior to the complete detachment of the two components. This provides a new route to obtain the free energy of mixing.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 22","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142813357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unusual salt effects on the time-dependent behavior of charge and shape anisotropic hectorite clay gels: Role of electric double layer (EDL) repulsive force. 不同寻常的盐对荷形各向异性钙钛矿粘土凝胶随时间变化行为的影响：双电层斥力的作用。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-14 DOI: 10.1063/5.0241130

Yee-Kwong Leong, Peta Clode

引用次数: 0

Measuring complex SFG: Characterizing a phase reference. 测量复杂的SFG：表征相位参考。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-14 DOI: 10.1063/5.0241557

Ziqing Xiong, Rebecca G Lynch, Emma F Gubbins, Mary Jane Shultz

引用次数: 0

Coupled methyl internal rotations with intermediate and low torsional barriers in 2,5-dimethylanisole investigated by microwave spectroscopy. 微波光谱法研究了2,5-二甲基甲醚中、低扭垒耦合甲基内旋。

IF 3.1 2区化学

Journal of Chemical Physics Pub Date : 2024-12-14 DOI: 10.1063/5.0235431

Haoyue Sun, Lynn Ferres, Isabelle Kleiner, Ha Vinh Lam Nguyen

{"title":"Coupled methyl internal rotations with intermediate and low torsional barriers in 2,5-dimethylanisole investigated by microwave spectroscopy.","authors":"Haoyue Sun, Lynn Ferres, Isabelle Kleiner, Ha Vinh Lam Nguyen","doi":"10.1063/5.0235431","DOIUrl":"https://doi.org/10.1063/5.0235431","url":null,"abstract":"We recorded and analyzed the microwave spectra of 2,5-dimethylanisole using a pulsed molecular jet Fourier transform microwave spectrometer and the newly developed Passage And Resonant-Impulse Synergy spectrometer across a frequency range of 2-26.5 GHz with support from quantum chemical calculations. Only one conformer was predicted and observed, where the methoxy group and its adjacent methyl group adopt anti-positions. The two methyl groups, located at the ortho- and meta-positions of the anisole ring, exhibit internal rotation, resulting in quintet splitting of all rotational transitions. The low torsional barrier of the m-methyl group, amounting to 65.723 611(84) cm-1, combined with the intermediate barrier of 451.664(19) cm-1 for the o-methyl group, presented challenges in the spectral analysis. Using the XIAM and BELGI-Cs-2Tops programs, we successfully fitted 460 torsional intrastate rotational transitions, allowing for precise determination of molecular parameters and internal rotation characteristics. The torsional barriers are compared to those in the related isomers 2,3-, 2,4-, and 3,4-dimethylanisole as well as other o- and m-substituted toluene derivatives.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"161 22","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142813152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0