Physical Chemistry Chemical Physics最新文献

{"title":"Molecular Dynamics of Synergistic Behavior at the Air-Water Interface: Mixed Cationic-anionic Fluorocarbon-Hydrocarbon Surfactants","authors":"Xiaolong Quan, Jing Xiong, Tong Tong, Jinqing Jiao, Jian-Ping Zou, Yuechang Wei","doi":"10.1039/d4cp04417g","DOIUrl":"https://doi.org/10.1039/d4cp04417g","url":null,"abstract":"Ecological concerns surrounding conventional aqueous film-forming foam extinguishing agents, predominantly composed of long-chain fluorocarbon surfactants, have spurred the need for innovation in eco-compatible substitutes, such as short-chain fluorocarbon surfactants. Molecular dynamics simulations are a valuable tool for studying the behavior of mixed surfactant systems at the air-water interface. We have conducted molecular dynamics simulations to investigate the interfacial behavior of a mixed cationic-anionic surfactant system, including N-[3-(Dimethylamino)propyl] perfluorobutanesulfonamide hydrochloride (PFB-MC) and 1-Octanesulfonic acid (1-OA). The simulations explored the effects of varying PFB-MC and 1-OA ratios on aggregation and adsorption. The results indicate that the equimolar 1:1 ratio produced more compact aggregates at the interface and achieved the most effective reduction in surface tension and the formation of the dense interfacial film. The study highlights the competitive adsorption phenomena between surfactants and counterions at the interface, providing insights through 1D and 2D density analyses into the impact of counterbalancing ions on aggregation. An increased PFB-MC concentration resulted in decreased hydrogen bonding with water, while 1-OA showed a higher tendency for hydrogen bonding, underscoring its hydrophilicity. These findings provide valuable insights into surfactant interfacial behavior and are instrumental in the development of advanced foam extinguishing agents suitable for environmental and industrial use.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"13 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470458","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":"Temperature-stable tunneling current in serial double quantum dots: insights from nonequilibrium green functions and Pauli spin blockade","authors":"David M. T. Kuo","doi":"10.1039/d4cp04224g","DOIUrl":"https://doi.org/10.1039/d4cp04224g","url":null,"abstract":"We theoretically investigate charge transport through serial double quantum dots (SDQDs) with strong electron correlations using nonequilibrium Green's function techniques. In the linear response regime, we compute the charge stability diagram and analyze the Coulomb oscillatory tunneling current, revealing both thermal and nonthermal broadening effects on the current spectra in relation to two gate voltages. In the nonlinear response regime, we focus on tunneling currents in SDQDs under the Pauli spin blockade (PSB) scenario. We find that current rectification with negative differential conductance is significantly degraded as temperature increases, making it challenging to distinguish between the inter-site spin triplet and singlet states. Notably, we observe a robust reversed tunneling current that remains stable against temperature variations, provided the resonant channel in the PSB scenario is coupled to the states of the right (left) electrode, which is fully occupied (unoccupied) by particles. This characteristic provides valuable insights for designing transistors capable of operating over a wide temperature range.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"19 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462515","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":"Anomalous membrane organization by omega-6 and omega-9 fatty acids","authors":"Sudha Porte, Swaratmika Pandia, Ankita Joardar, Deepashri Saraf, Aadil Pinjari, Hirak Chakraborty, Durba Sengupta","doi":"10.1039/d4cp04370g","DOIUrl":"https://doi.org/10.1039/d4cp04370g","url":null,"abstract":"Omega fatty acids are being marketed as healthy food supplements as they have been implicated in multiple pathophysiological conditions such as reducing plaque formation of Aβ peptide and inhibiting SARS-CoV-2 infection. Their mode of action has been hypothesized to be via membrane reorganization by the unsaturated acyl chains leading to the modulation of lipid-protein cross-talk. However, the lack of molecular details led us to evaluate the molecular effect of omega-6 (linolenic acid) and omega-9 (oleic acids) fatty acids on membrane organization using a consolidated approach of fluorescence spectroscopy and all-atom molecular dynamics simulation. Our results show that the effect of these omega fatty acids is sensitive to their protonation states. Contrary to the accepted notion that chain unsaturation causes membrane disordering, both experimental and simulation results demonstrate that the protonated linoleic acid promotes membrane ordering despite having two unsaturations at the fatty acyl chain. However, the protonated oleic fatty acid, with reduced unsaturation, disordered the acyl chain area of the lipid membranes. Equally surprisingly, deprotonated oleic acid orders, whereas deprotonated linoleic acid disorders the membrane core region. Interestingly, while the lipid order parameter measurements from simulations did not capture these subtle differences, the calculated rotational autocorrelation function of a membrane dye was in line with experimentally measured apparent rotational correlation times. Our work provides a comprehensive revised molecular picture of the effect of omega fatty acids on membranes and highlights the importance of rigorous comparative approaches as experimental and simulation studies in isolation can sometimes lead to inconsistent results.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"2 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462520","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":"Theoretical study on the kinetic behavior of Np(VI) reduction with hydroxylamine and its derivatives: substituent effect","authors":"Xin Huang, Qun-Yan Wu, Congzhi Wang, Jianhui Lan, Hongqing Wang, Weiqun Shi","doi":"10.1039/d4cp04616a","DOIUrl":"https://doi.org/10.1039/d4cp04616a","url":null,"abstract":"Spent fuel reprocessing entails controlling the valence state of Np and its direction in the Plutonium-Uranium Reduction Extraction (PUREX) process. Hydroxylamine (HA) and its derivatives are effective salt-free reductants that can reduce Np(VI) to Np(V) without further reduction. Experimentally, hydroxylamine, N-methylhydroxylamine (MHA) and N, N-dimethylhydroxylamine (DMHA) reduce Np(VI) at different reaction rates. To investigate the impact of methyl substitution on the reduction mechanism, we have theoretically studied the Np(VI) reduction reaction by HA, MHA and DMHA. The reduction of Np(VI) involved hydrogen atom transfer from these reductants. The two Np(VI) reductions by HA are via hydrogen transfer. The Np(VI) reduction by MHA and DMHA both undergoes the hydrogen atom transfer at first and the outer-sphere electron transfer at second. The rate-determining step for MHA and DMHA is the first Np(VI) reduction, and the energy barrier for DMHA is lower than that for MHA, which are 6.2 and 7.7 kcal mol-1, respectively. It suggests the reaction rate of DMHA reducing Np(VI) is faster than that of MHA with the influence of methyl, which follows the experiments. Finally, we also analyzed the bonding evolution by the quantum theory of atoms in molecules (QTAIM), interaction region indicator (IRI), Mayer bond order (MBO), localized molecular orbitals (LMO) and spin density. This study gives us a kinetic insight into the effect of methyl substitution on the reduction of Np(VI) by hydroxylamine, which provides in-depth Np(VI) reduction by hydroxylamine derivatives in spent fuel reprocessing.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462522","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":"Deciphering the full-length PrPC(23-231) Receptor and Characterizing the Size/Subphase-Dependent Impact of Aβ Oligomers on the PrPC(23-231) Receptor: Insights from Molecular Dynamics Simulations","authors":"Chuanbo Wang, Mengke Jia, Yvning Guan, Sajjad Ahmad, Jinfei Mei, Hongqi Ai","doi":"10.1039/d4cp04813j","DOIUrl":"https://doi.org/10.1039/d4cp04813j","url":null,"abstract":"As one of the cell surface receptors, cellular prion protein (PrPC) can bind Aβ oligomers (AβOs) and attenuate its neurotoxicity. However, there is still considerable controversy regarding the PrPC-AβO interaction, due to the polymorphism and varying size of the AβO species and void of full-length PrPC 3D structure. To solve the problem, we first complemented the missing residues in the residue-lacking crystal structure of PrPC and determine a 3D full-length PrPC receptor using “Alphafold2”. We subsequently investigated the complexes formed between the PrPC receptors—both the full-length and those missing the N-terminus—and a variety of Aβ42 species, including Aβ42 monomers, Aβ oligomers (AβOs) of varying sizes across two phases, as well as Aβ42 fibrils (AβFs), using molecular dynamics simulations. The simulated results indicate that the full-length PrPC receptor (23-231) employs a cavity, formed by its amino acid residues 44-51 and AA 95-110 regions, for Aβ42 binding. In contrast, the crystal structure of the PrPC receptor, typically lacking the N-terminal sequence (amino acids 23-87), provides a binding cavity composed of amino acids 95-110 and the C-terminal residues 131-161 to bind Aβ42, which is consistent with the diverse experimental outcomes observed (Nature 2009, 457(7233), 1128-1132; J. Am. Chem. Soc. 2022, 144(21), 9264-9270). This underscores the necessity of the novel full-length PrPC (PrPC23-231) 3D model for replicating experimental findings accurately. Additionally, we utilized both the full-length and truncated models of the PrPC receptor to clarify its disruptive effects on the growth of Aβ42 secondary nuclei structures (AβF) and its inhibitory impact on the disordered AβOs across two phases. This work provides molecular-level insights into the PrP-Aβ interaction, facilitating model selection for future experimental studies and identifying molecular targets for designing drugs intended to alleviate the toxicity of Aβ42 oligomers towards the PrPC receptor.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"12 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462600","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":"Quad-narrowband perfect absorption in near infrared for optical switching and sensing baesd on quasi-bound state in the continuum","authors":"Yuanwen Deng, Boxun Li, Lili Zeng, Qiang Wang, Zhengchao Ma, Yang Fan, Zhengzheng Shao, Chaosheng Deng","doi":"10.1039/d5cp00012b","DOIUrl":"https://doi.org/10.1039/d5cp00012b","url":null,"abstract":"The absorption of light based on quasi-BICs is a significant factor influencing the performance of solar cells and photodetectors. Nevertheless, the development of multiple narrowband perfect absorbers remains a significant challenge. In this study, three distinct types of BIC were first discovered to coexist within a metasurface structure. This paper proposes a dual grating metasurface (DGM) structure based on three classes of BICs supported in near-infrared spectroscopy. It achieves perfect absorption in four narrow bands dominated by quasi-BICs, with each of the peaks exceeding 99.5%. The physical mechanism of each resonance has been analysed using temporal coupled mode theory, which has revealed the existence of Symmtry-Protected BIC, Friedrich-Wintgen BIC and Fabry-Pérot BIC. Moreover, the underlying mechanisms of the distinct resonance modes are revealed through the multipolar decomposition of these resonances. The metasurface has significant potential for utilisation as an optical switch, which is capable of achieving optimal modulation depth, switching contrast, extinction ratio, and insertion loss of 99.9 %, 127932 %, -31.1 dB, and 0.0007 dB, respectively. The DGM structure offers superior quad-frequency synchronised optical switch in comparison to conventional optical switches. And it also exhibited a maximum sensitivity of 328.6 nm/RIU and a maximum FOM of 93.9 RIU-1 when used as a sensor. The work presented herein will facilitate the exploration of a novel avenue for the study of ultra-high performance multifunctional devices based on a multitude of types of BICs.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"19 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462517","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":"Molecular Dynamic simulation study on Hydrocarbon ladder polymer membranes for gas separation","authors":"Wenxuan Tian, Lidong Gong, Chunyang Yu, Yongfeng Zhou","doi":"10.1039/d4cp04588b","DOIUrl":"https://doi.org/10.1039/d4cp04588b","url":null,"abstract":"To address global environmental challenges and support the transition of energy systems, the study of CO2 capture and separation is at the fore front of scientific research. Utilizing membsranes based on Polymers of Intrinsic Microporosity (PIMs) for CO2 separation presents a promising approach. However, the mechanisms of CO2 separation in PIMs are not fully understood. In this study, an isobaric model combined with molecular dynamics (MD) simulation was used to explore the adsorptive and diffusive behaviors of CO2 and N2 in PIM membranes. We elucidated the gas separation mechanism by analyzing three critical aspects: microporous structure, adsorptive selectivity, and diffusive selectivity. The findings reveal that PIM membranes exhibit advantageous separation characteristics due to their large Brunauer-Emmett-Teller (BET) surface areas and Pore Limiting Diameters (PLD) that are more compatible with the size of CO2 molecules. Additionally, the difference in solvation free energy and diffusion rates between the two gases within the membranes significantly contributes to their selectivity. Specifically, CO2 diffuses within the membrane primarily through a hopping mechanism supplemented by diffusive motion, whereas N2 relies mainly on diffusion with less hopping. Since dissolution often takes precedence over diffusion in the separation process, it can sometimes lead to less effective diffusion for gas molecules. Moreover, the simulation results indicate that the diffusion behavior of CO2/N2 mixture in PIM membranes is governed by a solubility-driven separation mechanism. This work provides a theoretical foundation for understanding gas transport and separation mechanisms in PIM membranes.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"11 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462521","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":"A concise, efficient and accurate method for calculating the solid-liquid interfacial free energy","authors":"Yongquan Wu, Hang Cheng, HuaXing Miao, Kai Zhang, Jinglin You","doi":"10.1039/d4cp04346d","DOIUrl":"https://doi.org/10.1039/d4cp04346d","url":null,"abstract":"The solid-liquid (SL) interfacial free energy (IFE) is a pivotal property in many scenarios in physics, chemistry and even materials science. However, current experimental measurements and theoretical calculations of the SL IFE still suffer from problems of conciseness, efficiency and, above all, accuracy. For example, the currently dominant theoretical ‘3C’ methods, i.e. the cleaving potential method (CPM), the capillary fluctuations method (CFM) and the critical nucleus method (CNM), give results for the same SL interface that differ with each other by tens of per cent. In addition, these ‘3C’ methods are all computationally intensive. In this communication, we propose a new stable interface method (SIM) for the calculation of the SL IFE, which is concise, efficient and accurate at the same time. Based on the lever law in the isoenthalpic-isobaric phase diagram and the minimum interface principle, we can artificially control the morphology of the stable SL interface with different mean curvature in molecular dynamics simulations. The excellent agreement of the application results with the Gibbs-Thomson equation illustrates the accuracy of SIM, and hence the calculated SL IFE. The computational framework of SIM demonstrates the conciseness and the ultra-high computational efficiency. By applying SIM to three representative metals, it is demonstrated that SIM is superior to current ‘3C’ methods in terms of conciseness, efficiency and, in particular, accuracy. Finally, due to the universality of the mechanisms, this method should also be applicable to various materials, such as non-metals.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"25 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462599","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":"Decomposition pathways of isoprene-derived hydrotrioxides and their clustering abilities in the atmosphere","authors":"Emelda Ahongshangbam, Lauri Franzon, Thomas Golin Almeida, Galib Hasan, Benjamin Frandsen, Nanna Myllys","doi":"10.1039/d4cp04329d","DOIUrl":"https://doi.org/10.1039/d4cp04329d","url":null,"abstract":"In atmospheric gas-phase chemistry, hydrotrioxides (ROOOH) are formed as intermediates in the reactions of peroxyl radicals (RO<small>₂</small>) with OH radicals, and their stabilization has been confirmed experimentally by direct observation. In this study, we systematically investigated the probable decomposition pathways of isoprene-derived ROOOHs in the atmosphere. The kinetic analysis confirmed that the fast fragmentation of hydrotrioxides into their respective alkoxy radicals and hydroperoxyl radicals dominates over the other decomposition mechanisms. We also explored the decomposition of ROOOH proceeding via <small>³</small>(RO ··· HO<small>₂</small>) product complexes, through which an intermolecular hydrogen transfer results in the formation of alcohol and molecular oxygen with a relatively low energy barrier. Furthermore, we studied the clustering abilities of hydrotrioxides with various types of atmospheric vapors, particularly acids and amines. The results indicate that the binding strength of these hydrotrioxides with other vapors is too low to drive clustering process at ambient atmospheric concentrations, however, hydrotrioxides interact more strongly with bases and acid–base clusters than alcohols or hydroperoxides. These findings provide insight into the atmospheric stability and reactivity of hydrotrioxides, with implications for understanding their role in processes such as secondary organic aerosol formation.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"20 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462516","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":"Control of circular dichroism in ion yield of 3-methyl cyclopentanone with femtosecond laser pulses","authors":"Sagnik Das, Jayanta Ghosh, Vaseudevan Sudheendran, Simon Ranecky, Tonio Rosen, Nicolas Ladda, Han-gyeol Lee, Till-Jakob Stehling, Fabian Westmeier, Jochen Mikosch, Arne Senftleben, Thomas Baumert, Hendrike Braun","doi":"10.1039/d4cp04572f","DOIUrl":"https://doi.org/10.1039/d4cp04572f","url":null,"abstract":"Circular dichroism (CD) in ion yield in the gas phase is a promising chiral recognition technique. Combining it with broadband ultrafast laser pulses allows us to examine the possibility of coherent control. We used shaped femtosecond laser pulses to control the CD in ion yield of 3-methylcyclopentanone observed from a 1+1+1 resonance-enhanced multiphoton ionisation around 309 nm. The duration of the pulses is increased via their spectral width or a frequency chirp, and a pulse pair with adjustable delay is employed to study the effect on the CD in ion yield. Furthermore, we used strongly chirped pulses of different central wavelengths to control the observed anisotropy. A clear enhancement of the anisotropy can be achieved, and possible mechanisms are discussed.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"25 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462514","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}