Physical Chemistry Chemical Physics最新文献

{"title":"Study of the pH effects on water-oil-illite interfaces by molecular dynamics","authors":"Anderson Arboleda-Lamus, Leonardo Muñoz-Rugeles, Jorge M. del Campo, Nicolas Santos-Santos, Enrique Mejía","doi":"10.1039/d4cp03985h","DOIUrl":"https://doi.org/10.1039/d4cp03985h","url":null,"abstract":"Illite mineral is present in shale rocks and its wettability behavior is relevant for the oil and gas industry. In this work, the pH effects on the affinity between the (001) and (010) crystallographic planes of illite K2(Si7Al)(Al3Mg)O20(OH)4 and direct and inverse emulsions were studied by molecular dynamics simulations. To develop the simulations, the atomistic model of illite was constructed following the Löwenstein’s rule. The oily phase was modeled by heptane, toluene, and mixtures of heptane/heptanoic acid, heptane/heptanoate, heptane/hexylamine and heptane/hexylammonium. For the heptane/heptanoate and heptane/hexylammonium mixtures, Na+ and Cl- ions were used to neutralize the excess electrical charge of the droplets, respectively. The affinity of the mineral surface to the oil models was estimated by the contact angle for systems where it was possible; whereas, for systems where the droplets did not adhere to the mineral, a methodology based on the height of the droplet on the surface was proposed. The results show that in general, in the case of the inverse emulsions, water has a high affinity for both illite surfaces and its contact angle is below to 45º regardless to pH. However, the heptane/heptanoic acid inverse emulsions on the edge surface were the exception to that behavior, i.e., the contact angles calculated for the water droplets reveled mixed wettability because of the hydrogen bonds between the carboxylic functional groups (pH << 4.4) and the surface silanols and alumminols. On the other hand, oil droplets suspended in water did not adhere to the illite surfaces and contact angles were not measurable; nevertheless, the heptane/heptanoic acid droplets (pH << 4.4) showed heights around 2 and 4 Å above the basal and edge surfaces, respectively. This behavior was due to the hydrogen bonds formed between the carboxylic functional groups and the water molecules located on the mineral surfaces. Finally, the heptane/heptanoate (pH >> 4.4) and heptane/hexylammonium (pH << 10.64) droplets were localized at distances over 8 Å from the surface, presumably due to a charge repulsion effect between the mineral surface and the surface of the droplets.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"256 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841723","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}

{"title":"Thermodynamics and transport in molten chloride salts and their mixtures","authors":"Cillian Cockrell, Margaret-Ann Withington, Harvey Devereux, Alin Elena, Ilian Todorov, Zi-Kui Liu, Shunli Shang, John McCloy, Paul Bingham, Kostya Trachenko","doi":"10.1039/d4cp04180a","DOIUrl":"https://doi.org/10.1039/d4cp04180a","url":null,"abstract":"Molten salts are important in a number of energy applications, but the fundamental mechanisms operating in ionic liquids are poorly understood, particularly at higher temperatures. This is despite their candidacy for deployment in solar cells, next-generation nuclear reactors, and nuclear pyroprocessing. We perform extensive molecular dynamics simulations over a variety of molten chloride salt compositions at varying temperature and pressures to calculate the thermodynamic and transport properties of these liquids. Using recent developments in the theory of liquid thermophysical properties, we interpret our results on the basis of collective atomistic dynamics (phonons). We find that the properties of ionic liquids well explained by their collective dynamics, as in simple liquids. In particular, we relate the decrease of heat capacity, viscosity, and thermal conductivity to the loss of transverse phonons from the liquid spectrum. We observe the singular dependence of the isochoric heat capacity on the mean free path of phonons, and the obeyance of the Stokes-Einstein equation relating the viscosity to the mass diffusion. The transport properties of mixtures are more complicated compared to simple liquids, however viscosity and thermal conductivity are well guided by fundamental bounds proposed recently. The kinematic viscosity and thermal diffusivity lie very close to one another and obey the theoretical fundamental bounds determined solely by fundamental physical constants. Our results show that recent advances in the theoretical physics of liquids are applicable to molten salts mixtures, and therefore that the evolution and interplay of properties common to all liquids may act as a guide to a deeper understanding of these mixtures.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"10 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841724","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}

{"title":"Tunable Band Gaps and Conduction Band Edges of CdS/ZnS Heterostructures – A First-Principles-Based Prediction","authors":"Fengai Zhao, Dingbo Zhang, Yuxiang Ni, Hongyan Wang, Shuming Peng","doi":"10.1039/d4cp03827d","DOIUrl":"https://doi.org/10.1039/d4cp03827d","url":null,"abstract":"CdS/ZnS heterostructures/heterojunctions with tunable band gaps are promising photocatalysts for solar- or visible-light-driven H2 production through water splitting. To predict how the bandgap changes with the heterostructure composition, density functional theory calculations with a meta-GGA correction are conducted. It is found that the band gaps of CdS and ZnS are reduced by up to 14.5% and 43.3% in the heterostructures, respectively. The content of CdS in heterostructures plays a vital role in tuning the band gap and conduction band edge level. With the increasing number of CdS layers, the band gap first decreases and reaches a minimum value at (CdS)5/(ZnS)5, and then increases slightly. As a result, the (CdS)m/(ZnS)n (m≥3, m+n=10, or ≥30% of CdS) heterostructures attain desirable band gaps in the range of 2.06-2.25 eV for visible light absorption and 0.305-0.444 eV more negative conduction band edge than the reduction potential of H+/H2 for water splitting. These results suggest that the compositions of CdS/ZnS heterostructures can be adjusted to further improve the efficiencies of photocatalysts for visible light absorption and water splitting/H2 production.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"63 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832120","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}

{"title":"Dissociation of Adsorbates via Electronic Energy Transfer from Aromatic Thin Films","authors":"Erik Jensen","doi":"10.1039/d4cp03810j","DOIUrl":"https://doi.org/10.1039/d4cp03810j","url":null,"abstract":"Photofragment translational spectroscopy has been used to characterize the energetics and the cross sections for photodissociation of CH<small>₃</small>I and CF<small>₃</small>I adsorbed on thin films of a variety of aromatic molecules, initiated by near-UV light. Thin films (nominally 10 monolayers) of benzene, five substituted benzenes and two naphthalenes have been employed to study systematic changes in the photochemical activity. Illumination of these systems with 248nm light is found to result in a dissociation process for the CH<small>₃</small>I and CF<small>₃</small>I mediated by initial absorption in the aromatic thin film, followed by electronic energy transfer (EET) to the dissociating species. The effective cross sections for dissociation are found to be substantially increased via this mechanism (from 1.8x--20x), amounts differing depending on the aromatic molecule thin film used, and is connected to the aromatic photabsorption profile and the particular excited states being accessed. Distinctive translational energy distributions for the CH<small>₃</small> and CF<small>₃</small> photofragments are found to vary systematically for the different aromatic molecule thin film used, and are related to the energy of the lowest electronic excited singlet state of the aromatic molecule. The CH<small>₃</small> and CF<small>₃</small> photofragment kinetic energy distributions found for the aromatic thin films suggest that the dissociation occurs via EET to the <small>³</small>Q<small>₁</small> excited state of CH<small>₃</small>I and CF<small>₃</small>I.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"23 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841730","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}

{"title":"State-to-state scattering of highly vibrationally excited NO with argon at collision energies over 1 eV","authors":"Chatura Perera, Ethan Ross, Yang Liu, Arthur Suits, Hua Guo","doi":"10.1039/d4cp04259j","DOIUrl":"https://doi.org/10.1039/d4cp04259j","url":null,"abstract":"We present state-to-state differential cross sections for rotationally inelastic collisions of vibrationally excited NO X2Π (ν = 9) with Ar using a near-counterpropagating molecular beam geometry. These were obtained using the stimulated emission pumping technique coupled with velocity map imaging. Collision energies well over ~1 eV were achieved and rotational excitations up to ~ Δj = 60 recorded for the first time for inelastic collisions. This allowed us to investigate scattering of a diatomic molecule in a 2Π state which is initially well described by Hund’s case (a) into final states well described by Hund’s case (b) as the rotational level splitting becomes larger than the spin-orbit splitting. Differential cross sections for both parity-changing and parity-conserving collisions exhibit very similar structures at the high collision energies. Quantum scattering calculations have been carried out to obtain approximate integral cross sections, which confirm the high rotational excitation. These studies will take the arena of rotationally inelastic collisions to a new regime while providing insight into dynamics in extreme non-equilibrium conditions. Furthermore, these present a unique challenge to both quantum and quasiclassical scattering calculations to validate the methods and the potential energy surfaces used to assess their applicability in extreme conditions.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"148 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841725","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}

{"title":"Viedma deracemization mechanisms in self-assembly processes","authors":"Josep M. Ribó, David Hochberg, Thomas Buhse, Jean Claude Micheau","doi":"10.1039/d4cp03910f","DOIUrl":"https://doi.org/10.1039/d4cp03910f","url":null,"abstract":"Simulations on an ODE-based model shows that there are many common points between Viedma deracemization and chiral self-assemblies of achiral building blocks towards chiral nanoparticles. Both systems occur in a closed system with energy exchange but no matter exchange with the surroundings and show parallel reversible growth mechanisms which coexist with an irreversible cluster breaking (grinding). The various mechanisms of growth give rise to the formation of polymerization / depolymerization cycles while the consecutive transformation of achiral monomer into chiral cluster results into an indirect enantioselective autocatalysis. Deracemization occurs by the destabilization of the racemic non-equilibrium stationary state likely because of the excess of entropy production generated by the coupling of the reversible cluster growth mechanisms with grinding. Results show that the SMSB bias from the racemic composition occurs already at the oligomeric level of polymerization. Our model goes beyond the scope of the effect of grinding by the stirring of solutions which is thoroughly reported in supramolecular chirality. For instance, some unique characteristics, as those of a SMSB in closed systems, the simultaneous presence of different coupled reversible growth mechanisms, the activation by a depolymerization agent and the reincorporation of oligomers to the polymer growth reactions, could be adapted to replicator selectivity and to the emergence of biological homochirality scenarios.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832123","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}

{"title":"Enhanced phase prediction of high-entropy alloys through machine learning and data augmentation","authors":"Song Wu, Zihao Song, Jianwei Wang, Xiaobin Niu, Haiyuan Chen","doi":"10.1039/d4cp04496g","DOIUrl":"https://doi.org/10.1039/d4cp04496g","url":null,"abstract":"The phase structure information of high-entropy alloys (HEAs) is critical for their design and application, as different phase configurations are associated with distinct chemical and physical properties. However, the broad range of elements in HEAs presents significant challenges for precise experimental design and rational theoretical modeling and simulation. To address these challenges, machine learning (ML) methods have emerged as powerful tools for phase structure prediction. In this study, we use a dataset of 544 HEA configurations to predict phases, including 248 intermetallic, 131 solid solution, and 165 amorphous phases. To mitigate the limitations imposed by the small dataset size, we employ a Generative Adversarial Network (GAN) to augment the existing data. Our results show a significant improvement in model performance with data augmentation, achieving an average accuracy of 94.77% across ten random seeds. Validation on an independent dataset confirms the model's reliability and real-world applicability, achieving 100% prediction accuracy. We also predict FCC and BCC phases for SS HEAs based on elemental composition, achieving a peak accuracy of 98%. Furthermore, feature importance analysis identifies correlations between compositional features and phase formation tendencies, which are consistent with experimental observations. This work proposes an effective strategy to enhance the accuracy and generalizability of machine learning models in phase structure prediction, thus promoting the accelerated design of HEAs for a wide range of applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"38 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832121","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}

{"title":"Ferroelastic Phase Transition-Modulated Electronic Transport and Photoelectric Properties in Monolayer 1T' ZrCl₂","authors":"Yuehua Xu, He Sun, Jindian Chen, Qianqian Long, Haowen Xu","doi":"10.1039/d4cp04315d","DOIUrl":"https://doi.org/10.1039/d4cp04315d","url":null,"abstract":"Monolayer 1T' ZrCl₂ exhibits unique ferroelastic behavior with three structurally distinct variants (O1, O2, and O3), offering the potential for next-generation nanoelectronic and optoelectronic devices. This study investigates the electronic transport and optoelectronic properties of the O1 and O3 variants, with O3 serving as a representative for both O2 and O3 due to their structural symmetry. First-principles calculations and non-equilibrium Green's function analysis reveal that the O1 variant possesses exceptional electronic properties, including high electron mobility (1.44×10⁴ cm²/V·s) and a large current on/off ratio (10⁶), while the O3 variant shows high conductivity in both crystallographic directions. Optoelectronically, the O1 variant demonstrates strong anisotropy with a maximum photocurrent density of 6.57 μA/mm², photo responsivity of 0.37 A/W, and external quantum efficiency of 41.08% along the <em>a </em>direction, outperforming many 2D materials, whereas there is negligible response along the <em>b</em> direction. In contrast, the O3 variant exhibits a more balanced photoresponse with comparable performance in both directions. These findings provide insights into structure-property relationships in ferroelastic 2D materials and pave the way for developing phase transition-based multifunctional devices for applications in information processing, energy conversion, and sensing.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"47 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832119","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}

{"title":"Length-dependent water permeation through a graphene channel","authors":"Zi Wang, Shuang Li, Shiwu Gao, Jiaye Su","doi":"10.1039/d4cp03920c","DOIUrl":"https://doi.org/10.1039/d4cp03920c","url":null,"abstract":"Water confined in two-dimensional channels exhibits unique properties, such as rich morphology, specific phase transition and a low dielectric constant. In this work, molecular dynamics simulations have been used to study the water transport in two-dimensional graphene channels. The structures and dynamics of water under confinement show strong dependence on the channel length and thickness of the channels. In particular, there exists a critical channel length beyond which monolayer water forms square-like ice structures, leading to the rapid decrease in water flow that eventually ceases completely. The water flow for double-layer and three-layer systems exhibits a similar exponential decay but does not reach zero. The translocation time exhibits an excellent power-law behavior with an increase in the channel length, accounting for the exponential flow decay. The radial distribution function confirms the length-dependent liquid-to-ice phase transition of monolayer water and the liquid states for double-layer and three-layer systems. The formation of monolayer ice can be further supported by the increasing barriers in the potential of mean force and specific dipole distributions. Furthermore, the melting temperature of monolayer ice increases significantly with the increase in the channel length that can also be close to or even exceeds the boiling point at atmospheric pressure. These findings provide new physical insights into the extraordinary length-dependent water behaviors and suggest future experimental studies on high-temperature ice through the size control in nanochannels.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"25 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832122","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}

{"title":"Deep Learning-Driven Prediction of Chemical Addition Patterns for Carboncones and Fullerenes","authors":"Zhengda Li, Xuyang Chen, Yang Wang","doi":"10.1039/d4cp03238a","DOIUrl":"https://doi.org/10.1039/d4cp03238a","url":null,"abstract":"Carboncones and fullerenes are exemplary π-conjugated carbon nanomaterials with unsaturated, positively curved surfaces, enabling the attachment of atoms or functional groups to enhance their physicochemical properties. However, predicting and understanding the addition patterns in functionalized carboncones and fullerenes are extremely challenging due to the formidable complexity of the regioselectivity exhibited in the adducts. Existing predictive models fall short in systems where the carbon molecular framework undergoes severe distortion upon high degrees of addition. Here, we propose an incremental deep learning approach to predict regioselectivity in the hydrogenation of carboncones and chlorination of fullerenes. Utilizing exclusively graph-based features, our deep neural network (DNN) models rely solely on atomic connectivity, without requiring 3D molecular coordinates as input or iterative optimization of them. This advantage inherently avoids the risk of obtaining chemically unreasonable optimized structures, enabling the handling of highly distorted adducts. The DNN models allow us to study regioselectivity in hydrogenated carboncones of C<small>₇₀</small>H<small>₂₀</small> and C<small>₆₂</small>H<small>₁₆</small>, accommodating up to at least, 40 and 30 additional H atoms, respectively. Our approach also correctly predicts experimental addition patterns in C<small>₅₀</small>Cl<small>₁₀</small> and C<small>₇₆</small>Cl<small>_<em>n</em></small> (<em>n</em> = 18, 24, and 28), whereas in the latter cases all other known methods have proven unsuccessful. Compared to our previously developed topology-based models, the DNN’s superior predictive power and generalization ability make it a promising tool for investigating complex addition patterns in similar chemical systems.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"10 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832124","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}