Faraday Discussions最新文献_第7页

Predicting observable infrared signatures of nanosilicates in the diffuse interstellar medium 预测漫射星际介质中纳米硅酸盐的可观测红外特征

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-29 DOI: 10.1039/D3FD00055A

Sascha T. Zeegers, Joan Mariñoso Guiu, Francisca Kemper, Jonathan P. Marshall and Stefan T. Bromley

{"title":"Predicting observable infrared signatures of nanosilicates in the diffuse interstellar medium","authors":"Sascha T. Zeegers, Joan Mariñoso Guiu, Francisca Kemper, Jonathan P. Marshall and Stefan T. Bromley","doi":"10.1039/D3FD00055A","DOIUrl":"https://doi.org/10.1039/D3FD00055A","url":null,"abstract":"The destruction time scale of dust in the diffuse interstellar medium is estimated to be an order of magnitude shorter than its residence time. Nevertheless, dust is observed in the interstellar medium, leading to the conclusion that reformation and grain growth must take place. Direct observations of nanometre-sized silicate grains, the main constituent of interstellar dust, would provide a smoking gun for the occurrence of grain condensation in the diffuse interstellar medium. Here we employ quantum chemical calculations to obtain the mid-infrared (IR) optical properties of a library of Mg-end member silicate nanoparticles with olivine (Mg2SiO4) and pyroxene (MgSiO3) stoichiometries. We use this library as an input for a foreground-screen model to predict the spectral appearance of the absorption profile due to mixtures of bulk and nanoparticle silicates towards bright background sources. The mid-IR spectrum observed towards an O8V star or a carbon-rich Wolf–Rayet star starts to change when ∼3% of the silicate mass is in the form of nanosilicates. We predict that a 3–10% nanosilicate fraction can be detected with the James Webb Space Telescope (JWST) using the mid-IR instrument (MIRI). With our upcoming JWST observations using MIRI, we will be able to detect or place limits on the nanosilicate content in the diffuse interstellar medium, and thus potentially directly confirm interstellar dust formation.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"245 ","pages":" 609-619"},"PeriodicalIF":3.4,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24849654","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}

引用次数: 0

Streamers feeding the SVS13-A protobinary system: astrochemistry reveals accretion shocks? 为SVS13-A原双星系统提供能量的流光:天体化学揭示了吸积冲击?

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-28 DOI: 10.1039/D3FD00018D

Eleonora Bianchi, Ana López-Sepulcre, Cecilia Ceccarelli, Claudio Codella, Linda Podio, Mathilde Bouvier, Joan Enrique-Romero, Rafael Bachiller and Bertrand Lefloch

{"title":"Streamers feeding the SVS13-A protobinary system: astrochemistry reveals accretion shocks?","authors":"Eleonora Bianchi, Ana López-Sepulcre, Cecilia Ceccarelli, Claudio Codella, Linda Podio, Mathilde Bouvier, Joan Enrique-Romero, Rafael Bachiller and Bertrand Lefloch","doi":"10.1039/D3FD00018D","DOIUrl":"https://doi.org/10.1039/D3FD00018D","url":null,"abstract":"We report Atacama Large Millimeter/submillimeter Array (ALMA) high-angular resolution (∼50 au) observations of the binary system SVS13-A. More specifically, we analyse deuterated water (HDO) and sulfur dioxide (SO2) emission. The molecular emission is associated with both the components of the binary system, VLA4A and VLA4B. The spatial distribution is compared to that of formamide (NH2CHO), previously analysed in the system. Deuterated water shows an additional emitting component spatially coincident with the dust-accretion streamer, at a distance ≥120 au from the protostars, and at blue-shifted velocities (>3 km s−1 from the systemic velocities). We investigate the origin of the molecular emission in the streamer, in light of thermal sublimation temperatures calculated using updated binding energy (BE) distributions. We propose that the observed emission is produced by an accretion shock at the interface between the accretion streamer and the disk of VLA4A. Thermal desorption is not completely excluded in case the source is actively experiencing an accretion burst.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"245 ","pages":" 164-180"},"PeriodicalIF":3.4,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24849523","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}

引用次数: 0

Gating ion and fluid transport with chiral solvent† 手性溶剂的门控离子和流体传输。

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-24 DOI: 10.1039/D3FD00063J

Savannah Silva, Siddharth Singh, Ethan Cao, John T. Fourkas and Zuzanna S. Siwy

{"title":"Gating ion and fluid transport with chiral solvent†","authors":"Savannah Silva, Siddharth Singh, Ethan Cao, John T. Fourkas and Zuzanna S. Siwy","doi":"10.1039/D3FD00063J","DOIUrl":"10.1039/D3FD00063J","url":null,"abstract":"The development of modern membranes for ionic separations and energy-storage devices such as supercapacitors depends on the description of ions at solid interfaces, as is often provided by the electrical double layer (EDL) model. The classical EDL model ignores, however, important factors such as possible spatial organization of solvent at the interface and the influence of the solvent on the spatial dependence of the electrochemical potential; these effects in turn govern electrokinetic phenomena. Here we provide a molecular-level understanding of how solvent structure can dictate ionic distributions at interfaces using a model system of a polar, aprotic solvent, propylene carbonate, in its enantiomerically pure and racemic forms, at a silica interface. We link the interfacial structure to the tuning of ionic and fluid transport by the chirality of the solvent and the salt concentration. The results of nonlinear spectroscopic experiments and electrochemical measurements suggest that the solvent exhibits lipid-bilayer-like interfacial organization, with a structure that is dependent on the solvent chirality. The racemic form creates highly ordered layered structure that dictates local ionic concentrations, such that the effective surface potential becomes positive in a wide range of electrolyte concentrations. The enantiomerically pure form exhibits weaker ordering at the silica surface, which leads to a lower effective surface charge induced by ions partitioning into the layered structure. The surface charge in silicon nitride and polymer pores is probed through the direction of electroosmosis that the surface charges induce. Our findings add a new dimension to the nascent field of chiral electrochemistry, and emphasize the importance of including solvent molecules in descriptions of solid–liquid interfaces.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"246 ","pages":" 508-519"},"PeriodicalIF":3.4,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10141034","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}

引用次数: 0

Ion adsorption and hydration forces: a comparison of crystalline mica vs. amorphous silica surfaces† 离子吸附和水合力：结晶云母与无定形二氧化硅表面的比较†

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-17 DOI: 10.1039/D3FD00049D

Igor Siretanu, Simone R. van Lin and Frieder Mugele

{"title":"Ion adsorption and hydration forces: a comparison of crystalline mica vs. amorphous silica surfaces†","authors":"Igor Siretanu, Simone R. van Lin and Frieder Mugele","doi":"10.1039/D3FD00049D","DOIUrl":"https://doi.org/10.1039/D3FD00049D","url":null,"abstract":"Hydration forces are ubiquitous in nature and technology. Yet, the characterization of interfacial hydration structures and their dependence on the nature of the substrate and the presence of ions have remained challenging and controversial. We present a systematic study using dynamic Atomic Force Microscopy of hydration forces on mica surfaces and amorphous silica surfaces in aqueous electrolytes containing chloride salts of various alkali and earth alkaline cations of variable concentrations at pH values between 3 and 9. Our measurements with ultra-sharp AFM tips demonstrate the presence of both oscillatory and monotonically decaying hydration forces of very similar strength on both atomically smooth mica and amorphous silica surfaces with a roughness comparable to the size of a water molecule. The characteristic range of the forces is approximately 1 nm, independent of the fluid composition. Force oscillations are consistent with the size of water molecules for all conditions investigated. Weakly hydrated Cs+ ions are the only exception: they disrupt the oscillatory hydration structure and induce attractive monotonic hydration forces. On silica, force oscillations are also smeared out if the size of the AFM tip exceeds the characteristic lateral scale of the surface roughness. The observation of attractive monotonic hydration forces for asymmetric systems suggests opportunities to probe water polarization.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"246 ","pages":" 274-295"},"PeriodicalIF":3.4,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2023/fd/d3fd00049d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41228609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Surface polarization enhances ionic transport and correlations in electrolyte solutions nanoconfined by conductors† 表面极化增强了由导体纳米约束的电解质溶液中的离子传输和相关性。

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-16 DOI: 10.1039/D3FD00028A

Felipe Jiménez-Ángeles, Ali Ehlen and Monica Olvera de la Cruz

{"title":"Surface polarization enhances ionic transport and correlations in electrolyte solutions nanoconfined by conductors†","authors":"Felipe Jiménez-Ángeles, Ali Ehlen and Monica Olvera de la Cruz","doi":"10.1039/D3FD00028A","DOIUrl":"10.1039/D3FD00028A","url":null,"abstract":"Layered materials that perform mixed electron and ion transport are promising for energy harvesting, water desalination, and bioinspired functionalities. These functionalities depend on the interaction between ionic and electronic charges on the surface of materials. Here we investigate ion transport by an external electric field in an electrolyte solution confined in slit-like channels formed by two surfaces separated by distances that fit only a few water layers. We study different electrolyte solutions containing monovalent, divalent, and trivalent cations, and we consider walls made of non-polarizable surfaces and conductors. We show that considering the surface polarization of the confining surfaces can result in a significant increase in ionic conduction. The ionic conductivity is increased because the conductors’ screening of electrostatic interactions enhances ionic correlations, leading to faster collective transport within the slit. While important, the change in water’s dielectric constant in confinement is not enough to explain the enhancement of ion transport in polarizable slit-like channels.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"246 ","pages":" 576-591"},"PeriodicalIF":3.4,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9768605","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}

引用次数: 1

Disentangling 1/f noise from confined ion dynamics 从受限离子动力学中分离1/f噪声

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-16 DOI: 10.1039/D3FD00035D

Paul Robin, Mathieu Lizée, Qian Yang, Théo Emmerich, Alessandro Siria and Lydéric Bocquet

{"title":"Disentangling 1/f noise from confined ion dynamics","authors":"Paul Robin, Mathieu Lizée, Qian Yang, Théo Emmerich, Alessandro Siria and Lydéric Bocquet","doi":"10.1039/D3FD00035D","DOIUrl":"https://doi.org/10.1039/D3FD00035D","url":null,"abstract":"Ion transport through biological and solid-state nanochannels is known to be a highly noisy process. The power spectrum of current fluctuations is empirically known to scale like the inverse of frequency, following the long-standing yet poorly understood Hooge's law. Here, we report measurements of current fluctuations across nanometer-scale two-dimensional channels with different surface properties. The structure of fluctuations is found to depend on the channel's material. While in pristine channels current fluctuations scale like 1/f1+a with a = 0–0.5, the noise power spectrum of activated graphite channels displays different regimes depending on frequency. Based on these observations, we develop a theoretical formalism directly linking ion dynamics and current fluctuations. We predict that the noise power spectrum takes the form 1/f × Schannel(f), where 1/f fluctuations emerge in fluidic reservoirs on both sides of the channel and Schannel describes fluctuations inside it. Deviations to Hooge's law thus allow direct access to the ion transport dynamics of the channel – explaining the entire phenomenology observed in experiments on 2D nanochannels. Our results demonstrate how current fluctuations can be used to characterize nanoscale ion dynamics.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"246 ","pages":" 556-575"},"PeriodicalIF":3.4,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41228704","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}

引用次数: 1

Hunting for interstellar molecules: rotational spectra of reactive species† 寻找星际分子:反应物质的旋转光谱†

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-14 DOI: 10.1039/D3FD00052D

Cristina Puzzarini, Silvia Alessandrini, Luca Bizzocchi and Mattia Melosso

引用次数: 1

Pulsed electrolysis – explained† 脉冲电解-解释。

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-03-10 DOI: 10.1039/D3FD00030C

T. Miličić, M. Sivasankaran, C. Blümner, A. Sorrentino and T. Vidaković-Koch

{"title":"Pulsed electrolysis – explained†","authors":"T. Miličić, M. Sivasankaran, C. Blümner, A. Sorrentino and T. Vidaković-Koch","doi":"10.1039/D3FD00030C","DOIUrl":"10.1039/D3FD00030C","url":null,"abstract":"Lately, there has been high interest in electrolysis under dynamic conditions, the so-called pulsed electrolysis. Different studies have shown that in pulsed electrolysis, selectivity towards certain products can be improved compared to steady-state operation. Many groups also demonstrated that the selectivity can be tuned by selection of pulsing profile, potential limits, as well as frequency of the change. To explain the origin of this improvement, some modeling studies have been performed. However, it seems that a theoretical framework to study this effect is still missing. In the present contribution, we suggest a theoretical framework of nonlinear frequency response analysis for the evaluation of the process improvement under pulsed electrolysis conditions. Of special interest is the DC component, which determines how much the mean output value under dynamic conditions will be different from the value under steady-state conditions. Therefore, the DC component can be considered as a measure of process improvement under dynamic conditions compared to the steady-state operation. We show that the DC component is directly dependent on nonlinearities of the electrochemical process and demonstrate how this DC component can be calculated theoretically as well as how it can be obtained from measurements.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"246 ","pages":" 179-197"},"PeriodicalIF":3.4,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2023/fd/d3fd00030c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9815324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 1

Preferential destruction of NH2-bearing complex interstellar molecules via gas-phase proton-transfer reactions 通过气相质子转移反应优先破坏含nh2复合星际分子

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-02-27 DOI: 10.1039/D3FD00014A

Robin T. Garrod and Eric Herbst

{"title":"Preferential destruction of NH2-bearing complex interstellar molecules via gas-phase proton-transfer reactions","authors":"Robin T. Garrod and Eric Herbst","doi":"10.1039/D3FD00014A","DOIUrl":"https://doi.org/10.1039/D3FD00014A","url":null,"abstract":"Complex, nitrogen-bearing interstellar molecules, especially amines, are targets of particular interest for detection in star- and planet-forming regions, due to their possible relevance to prebiotic chemistry. However, these NH2-bearing molecules are not universally detected in sources where other, oxygen-bearing complex organic molecules (COMs) are often plentiful. Nevertheless, recent astrochemical models have often predicted large abundances for NH2-bearing complex organics, based on their putative production on dust grains. Here we investigate a range of new gas-phase proton-transfer reactions and their influence on the destruction of COMs. As in past studies, reactions between protonated COMs and ammonia (NH3) are found to be important in prolonging gas-phase COM lifetimes. However, for molecules with proton affinities (PA) greater than that of ammonia, proton-transfer reactions result in drastic reductions in abundances and lifetimes. Ammonia acts as a sink for proton transfer from low-PA COMs, while passing on protons to high-PA species; dissociative recombination with electrons then destroys the resulting ions. Species strongly affected include methylamine (CH3NH2), urea (NH2C(O)NH2) and others bearing the NH2 group. The abundances of these species show a sharp time dependence, indicating that their detectability may rest on the precise chemical age of the source. Rapid gas-phase destruction of glycine (NH2CH2COOH) in the models suggests that its future detection may be yet more challenging than previously hoped.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"245 ","pages":" 541-568"},"PeriodicalIF":3.4,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24849635","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}

引用次数: 0

Mapping the photochemistry of cyclopentadiene: from theory to ultrafast X-ray scattering† 环戊二烯的光化学映射:从理论到超快x射线散射

IF 3.4 3区化学

Faraday Discussions Pub Date : 2023-02-10 DOI: 10.1039/D2FD00176D

Lauren Bertram, Peter M. Weber and Adam Kirrander

{"title":"Mapping the photochemistry of cyclopentadiene: from theory to ultrafast X-ray scattering†","authors":"Lauren Bertram, Peter M. Weber and Adam Kirrander","doi":"10.1039/D2FD00176D","DOIUrl":"https://doi.org/10.1039/D2FD00176D","url":null,"abstract":"The photoinduced ring-conversion reaction when cyclopentadiene (CP) is excited at 5.10 eV is simulated using surface-hopping semiclassical trajectories with XMS(3)-CASPT2(4,4)/cc-pVDZ electronic structure theory. In addition, PBE0/def2-SV(P) is employed for ground state propagation of the trajectories. The dynamics is propagated for 10 ps, mapping both the nonadiabatic short-time dynamics (<300 fs) and the increasingly statistical dynamics on the electronic ground state. The short-time dynamics yields a mixture of hot CP and bicyclo[2.1.0]pentene (BP), with the two products reached via different regions of the same conical intersection seam. On the ground state, we observe slow conversion from BP to CP which is modelled by RRKM theory with a transition state determined using PBE0/def2-TZVP. The CP products are furthermore associated with ground state hydrogen shifts and some H-atom dissociation. Finally, the prospects for detailed experimental mapping using novel ultrafast X-ray scattering experiments are discussed and observables for such experiments are predicted. In particular, we assess the possibility of retrieving electronic states and their populations alongside the structural dynamics.","PeriodicalId":76,"journal":{"name":"Faraday Discussions","volume":"244 ","pages":" 269-293"},"PeriodicalIF":3.4,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2023/fd/d2fd00176d?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3694282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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