André Niebur, Eugen Klein, Rostyslav Lesyuk, Christian Klinke, Jannika Lauth
Quasi two-dimensional (2D) colloidal synthesis made quantum confinement readily accessible in perovskites, generating additional momentum in perovskite LED research and lasing. Ultrathin perovskite layers exhibit high exciton binding energies and beneficial charge transport properties interesting for solar cells. In 2D perovskites, the combination of layers with different thickness helps to direct charge carriers in a targeted manner toward thicker layers with a smaller bandgap. However, detailed knowledge about the mechanisms by which excitons and charge carriers funnel and recombine in these structures is lacking. Here, we characterize colloidal 2D methylammonium lead bromide (MAPbBr3) Ruddlesden-Popper perovskites with a broad combination of layers (n = 3 to 10, and bulk fractions with n > 10) in one stack by femtosecond transient absorption spectroscopy and time-resolved photoluminescence, which gives comprehensive insights into the complexity of funneling and recombination processes. We find that after photoexcitation second- and third-order processes dominate in MAPbBr3 nanosheets, which indicates exciton-exciton annihilation (EEA) and Auger recombination. Long-lived excitons in thin layers (e.g., n = 5, Eb = 136 meV) funnel into high n with t = 10-50 ps, which decreases their exciton binding energy below kB T = 26 meV ( T = 300K) and leads to radiative recombination. Parallel and consecutive funneling compete with exciton trapping processes, making funneling an excellent tool to overcome exciton self-trapping when high-quality n-n interfaces are present. Free charge carriers in high n regions on the other hand facilitate radiative recombination and EEA is bypassed, which is desirable for LED and lasing applications.
准二维（2D）胶体合成技术使得量子禁锢技术在包晶石中的应用变得非常容易，从而为包晶发光二极管（perovskiteLED）的研究和发光带来了新的动力。超薄的过氧化物层具有很高的激子结合能和有益的电荷传输特性，对太阳能电池很有意义。在二维过氧化物中，不同厚度层的组合有助于有针对性地将电荷载流子引向带隙较小的较厚层。然而，人们对激子和电荷载流子在这些结构中的漏斗和重组机制还缺乏详细的了解。在这里，我们通过飞秒瞬态吸收光谱和时间分辨光致发光表征了胶体二维甲基溴化铵铅（MAPbBr3）Ruddlesden-Popper 包晶石，这些包晶石具有广泛的层组合（n =3 到 10，以及 n > 10 的体分数），从而全面揭示了漏斗和重组过程的复杂性。我们发现，在 MAPbBr3 纳米片中，光激发后的二阶和三阶过程占主导地位，这表明存在激子-激子湮灭（EEA）和奥格重组。薄层中的长寿命激子（如 n = 5，Eb = 136 meV）在 t = 10-50 ps 的时间内漏斗进入高 n，从而使激子结合能降低到 kB T = 26 meV 以下（T = 300K），导致辐射对撞。平行漏斗效应和连续漏斗效应与激子捕获过程相竞争，因此当存在高质量 n-n 接口时，漏斗效应是克服激子自捕获的绝佳工具。另一方面，高 n 区中的自由电荷载流子会促进辐射重组，从而绕过 EEA，这对于 LED 和发光应用来说是非常理想的。
{"title":"Understanding the Optoelectronic Processes in Colloidal 2D Multi-Layered MAPbBr3 Perovskite Nanosheets: Funneling, Recombination and Self-Trapped Excitons","authors":"André Niebur, Eugen Klein, Rostyslav Lesyuk, Christian Klinke, Jannika Lauth","doi":"arxiv-2408.04571","DOIUrl":"https://doi.org/arxiv-2408.04571","url":null,"abstract":"Quasi two-dimensional (2D) colloidal synthesis made quantum confinement\u0000readily accessible in perovskites, generating additional momentum in perovskite\u0000LED research and lasing. Ultrathin perovskite layers exhibit high exciton\u0000binding energies and beneficial charge transport properties interesting for\u0000solar cells. In 2D perovskites, the combination of layers with different\u0000thickness helps to direct charge carriers in a targeted manner toward thicker\u0000layers with a smaller bandgap. However, detailed knowledge about the mechanisms\u0000by which excitons and charge carriers funnel and recombine in these structures\u0000is lacking. Here, we characterize colloidal 2D methylammonium lead bromide\u0000(MAPbBr3) Ruddlesden-Popper perovskites with a broad combination of layers (n =\u00003 to 10, and bulk fractions with n > 10) in one stack by femtosecond transient\u0000absorption spectroscopy and time-resolved photoluminescence, which gives\u0000comprehensive insights into the complexity of funneling and recombination\u0000processes. We find that after photoexcitation second- and third-order processes\u0000dominate in MAPbBr3 nanosheets, which indicates exciton-exciton annihilation\u0000(EEA) and Auger recombination. Long-lived excitons in thin layers (e.g., n = 5,\u0000Eb = 136 meV) funnel into high n with t = 10-50 ps, which decreases their\u0000exciton binding energy below kB T = 26 meV ( T = 300K) and leads to radiative\u0000recombination. Parallel and consecutive funneling compete with exciton trapping\u0000processes, making funneling an excellent tool to overcome exciton self-trapping\u0000when high-quality n-n interfaces are present. Free charge carriers in high n\u0000regions on the other hand facilitate radiative recombination and EEA is\u0000bypassed, which is desirable for LED and lasing applications.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Constantin Schwetlick, Max Schammer, Arnulf Latz, Birger Horstmann
Modelling electrolytes accurately on both a nanoscale and cell level can contribute to improving battery chemistries.[Armand and Tarascon, Nature, 2008, 451, 652-657] We previously presented a thermodynamic continuum model for electrolytes.[arXiv:2010.14915] In this paper we include solvation interactions between the ions and solvent, which alter the structure of the electochemical double layer (EDL). We are able to combine a local solvation model -- permitting examination of the interplay between electric forces and the ion-solvent binding -- with a full electrolyte model. Using this, we can investigate double layer structures for a wide range of electrolytes, especially including highly concentrated solutions. We find that some of the parameters of our model significantly affect the solvent concentration at the electrode surface, and thereby the rate of solvent decomposition. Firstly, an increased salt concentration weakens the solvation shells, making it possible to strip the solvent in the EDL before the ions reach the surface. The strength of the ion-solvent interaction also affects at which potential difference the solvation shells removed. We are therefore able to qualitatively predict EDL structures for different electrolytes based on parameters like molecule size, solvent binding energy and salt concentration.
{"title":"Modeling the Influence of Solvation on the Electrochemical Double Layer of Salt / Solvent Mixtures","authors":"Constantin Schwetlick, Max Schammer, Arnulf Latz, Birger Horstmann","doi":"arxiv-2408.04314","DOIUrl":"https://doi.org/arxiv-2408.04314","url":null,"abstract":"Modelling electrolytes accurately on both a nanoscale and cell level can\u0000contribute to improving battery chemistries.[Armand and Tarascon, Nature, 2008,\u0000451, 652-657] We previously presented a thermodynamic continuum model for\u0000electrolytes.[arXiv:2010.14915] In this paper we include solvation interactions\u0000between the ions and solvent, which alter the structure of the electochemical\u0000double layer (EDL). We are able to combine a local solvation model --\u0000permitting examination of the interplay between electric forces and the\u0000ion-solvent binding -- with a full electrolyte model. Using this, we can\u0000investigate double layer structures for a wide range of electrolytes,\u0000especially including highly concentrated solutions. We find that some of the\u0000parameters of our model significantly affect the solvent concentration at the\u0000electrode surface, and thereby the rate of solvent decomposition. Firstly, an\u0000increased salt concentration weakens the solvation shells, making it possible\u0000to strip the solvent in the EDL before the ions reach the surface. The strength\u0000of the ion-solvent interaction also affects at which potential difference the\u0000solvation shells removed. We are therefore able to qualitatively predict EDL\u0000structures for different electrolytes based on parameters like molecule size,\u0000solvent binding energy and salt concentration.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"195 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniil A. Boiko, Thiago Reschützegger, Benjamin Sanchez-Lengeling, Samuel M. Blau, Gabe Gomes
Molecular representation is a foundational element in our understanding of the physical world. Its importance ranges from the fundamentals of chemical reactions to the design of new therapies and materials. Previous molecular machine learning models have employed strings, fingerprints, global features, and simple molecular graphs that are inherently information-sparse representations. However, as the complexity of prediction tasks increases, the molecular representation needs to encode higher fidelity information. This work introduces a novel approach to infusing quantum-chemical-rich information into molecular graphs via stereoelectronic effects. We show that the explicit addition of stereoelectronic interactions significantly improves the performance of molecular machine learning models. Furthermore, stereoelectronics-infused representations can be learned and deployed with a tailored double graph neural network workflow, enabling its application to any downstream molecular machine learning task. Finally, we show that the learned representations allow for facile stereoelectronic evaluation of previously intractable systems, such as entire proteins, opening new avenues of molecular design.
{"title":"Advancing Molecular Machine (Learned) Representations with Stereoelectronics-Infused Molecular Graphs","authors":"Daniil A. Boiko, Thiago Reschützegger, Benjamin Sanchez-Lengeling, Samuel M. Blau, Gabe Gomes","doi":"arxiv-2408.04520","DOIUrl":"https://doi.org/arxiv-2408.04520","url":null,"abstract":"Molecular representation is a foundational element in our understanding of\u0000the physical world. Its importance ranges from the fundamentals of chemical\u0000reactions to the design of new therapies and materials. Previous molecular\u0000machine learning models have employed strings, fingerprints, global features,\u0000and simple molecular graphs that are inherently information-sparse\u0000representations. However, as the complexity of prediction tasks increases, the\u0000molecular representation needs to encode higher fidelity information. This work\u0000introduces a novel approach to infusing quantum-chemical-rich information into\u0000molecular graphs via stereoelectronic effects. We show that the explicit\u0000addition of stereoelectronic interactions significantly improves the\u0000performance of molecular machine learning models. Furthermore,\u0000stereoelectronics-infused representations can be learned and deployed with a\u0000tailored double graph neural network workflow, enabling its application to any\u0000downstream molecular machine learning task. Finally, we show that the learned\u0000representations allow for facile stereoelectronic evaluation of previously\u0000intractable systems, such as entire proteins, opening new avenues of molecular\u0000design.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olga I. Vinogradova, Elena F. Silkina, Evgeny S. Asmolov
When we place conducting bodies in electrolyte solutions, their surface potential $Phi_s$ appears to be much smaller in magnitude than the intrinsic one $Phi_0$ and normally does not obey the classical electrostatic boundary condition of a constant surface potential expected for conductors. In this paper, we demonstrate that an explanation of these observations can be obtained by postulating that diffuse ions condense at the "wall" due to a reduced permittivity of a solvent. For small values of $Phi_0$ the surface potential responds linearly. On increasing $Phi_0$ further $Phi_s$ augments nonlinearly and then saturates to a constant value. Analytical approximations for $Phi_s$ derived for these three distinct modes show that it always adjusts to salt concentration, which is equivalent to a violation of the constant potential condition. The latter would be appropriate for highly dilute solutions, but only if $Phi_0$ is small. Surprisingly, when the plateau with high $Phi_s$ is reached, the conductor surface switches to a constant charge density condition normally expected for insulators. Our results are directly relevant for conducting electrodes, mercury drops, colloidal metallic particles and more.
{"title":"Surface potentials of conductors in electrolyte solutions","authors":"Olga I. Vinogradova, Elena F. Silkina, Evgeny S. Asmolov","doi":"arxiv-2408.04434","DOIUrl":"https://doi.org/arxiv-2408.04434","url":null,"abstract":"When we place conducting bodies in electrolyte solutions, their surface\u0000potential $Phi_s$ appears to be much smaller in magnitude than the intrinsic\u0000one $Phi_0$ and normally does not obey the classical electrostatic boundary\u0000condition of a constant surface potential expected for conductors. In this\u0000paper, we demonstrate that an explanation of these observations can be obtained\u0000by postulating that diffuse ions condense at the \"wall\" due to a reduced\u0000permittivity of a solvent. For small values of $Phi_0$ the surface potential responds linearly. On\u0000increasing $Phi_0$ further $Phi_s$ augments nonlinearly and then saturates to\u0000a constant value. Analytical approximations for $Phi_s$ derived for these\u0000three distinct modes show that it always adjusts to salt concentration, which\u0000is equivalent to a violation of the constant potential condition. The latter\u0000would be appropriate for highly dilute solutions, but only if $Phi_0$ is\u0000small. Surprisingly, when the plateau with high $Phi_s$ is reached, the\u0000conductor surface switches to a constant charge density condition normally\u0000expected for insulators. Our results are directly relevant for conducting\u0000electrodes, mercury drops, colloidal metallic particles and more.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xavier R. Advincula, Kara D. Fong, Angelos Michaelides, Christoph Schran
Water's ability to autoionize into hydroxide and hydronium ions profoundly influences surface properties, rendering interfaces either basic or acidic. While it is well-established that the water-air interface is acidic, a critical knowledge gap exists in technologically relevant surfaces like the graphene-water interface. Here we use machine learning-based simulations with first-principles accuracy to unravel the behavior of the hydroxide and hydronium ions at the graphene-water interface. Our findings reveal that the graphene-water interface is acidic, with the hydronium ion predominantly residing in the first contact layer of water. In contrast, the hydroxide ion exhibits a bimodal distribution, found both near the surface and towards the interior layers. Analysis of the underlying electronic structure reveals strong polarization effects, resulting in counterintuitive charge rearrangement. Proton propensity to the graphene-water interface challenges the interpretation of surface experiments and is expected to have far-reaching consequences for ion conductivity, interfacial reactivity, and proton-mediated processes.
{"title":"The graphene-water interface is acidic","authors":"Xavier R. Advincula, Kara D. Fong, Angelos Michaelides, Christoph Schran","doi":"arxiv-2408.04487","DOIUrl":"https://doi.org/arxiv-2408.04487","url":null,"abstract":"Water's ability to autoionize into hydroxide and hydronium ions profoundly\u0000influences surface properties, rendering interfaces either basic or acidic.\u0000While it is well-established that the water-air interface is acidic, a critical\u0000knowledge gap exists in technologically relevant surfaces like the\u0000graphene-water interface. Here we use machine learning-based simulations with\u0000first-principles accuracy to unravel the behavior of the hydroxide and\u0000hydronium ions at the graphene-water interface. Our findings reveal that the\u0000graphene-water interface is acidic, with the hydronium ion predominantly\u0000residing in the first contact layer of water. In contrast, the hydroxide ion\u0000exhibits a bimodal distribution, found both near the surface and towards the\u0000interior layers. Analysis of the underlying electronic structure reveals strong\u0000polarization effects, resulting in counterintuitive charge rearrangement.\u0000Proton propensity to the graphene-water interface challenges the interpretation\u0000of surface experiments and is expected to have far-reaching consequences for\u0000ion conductivity, interfacial reactivity, and proton-mediated processes.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compounds harboring active valence electrons, such as unconventional stoichiometric compounds of main group elements including sodium, chlorine, and carbon, have conventionally been perceived as unstable under ambient conditions, requiring extreme conditions including extra-high pressure environments for stability. Recent discoveries challenge this notion, showcasing the ambient stability of two-dimensional Na2Cl and other unconventional stoichiometric compounds on reduced graphene oxide (rGO) membranes. Focusing on the Na2Cl crystal as a case study, we reveal a mechanism wherein electron delocalization on the aromatic rings of graphene effectively mitigates the reactivity of Na2Cl, notably countering oxygen-induced oxidation--a phenomenon termed the Surface Delocalization-Induced Electron Trap (SDIET) mechanism. Theoretical calculations also show a substantial activation energy barrier emerges, impeding oxygen infiltration into and reaction with Na2Cl. The remarkable stability was further demonstrated by the experiment that Na2Cl crystals on rGO membranes remain almost intact even after prolonged exposure to a pure oxygen atmosphere for 9 days. The discovered SDIET mechanism presents a significant leap in stabilizing chemically active substances harboring active valence electrons under ambient conditions. Its implications transcend unconventional stoichiometric compounds, encompassing main group and transition element compounds, potentially influencing various scientific disciplines.
{"title":"Stability Mechanisms of Unconventional Stoichiometric Crystals Exampled by Two-Dimensional Na2Cl on Graphene under Ambient Conditions","authors":"Liuhua Mu, Xuchang Su, Haiping Fang, Lei Zhang","doi":"arxiv-2408.04286","DOIUrl":"https://doi.org/arxiv-2408.04286","url":null,"abstract":"Compounds harboring active valence electrons, such as unconventional\u0000stoichiometric compounds of main group elements including sodium, chlorine, and\u0000carbon, have conventionally been perceived as unstable under ambient\u0000conditions, requiring extreme conditions including extra-high pressure\u0000environments for stability. Recent discoveries challenge this notion,\u0000showcasing the ambient stability of two-dimensional Na2Cl and other\u0000unconventional stoichiometric compounds on reduced graphene oxide (rGO)\u0000membranes. Focusing on the Na2Cl crystal as a case study, we reveal a mechanism\u0000wherein electron delocalization on the aromatic rings of graphene effectively\u0000mitigates the reactivity of Na2Cl, notably countering oxygen-induced\u0000oxidation--a phenomenon termed the Surface Delocalization-Induced Electron Trap\u0000(SDIET) mechanism. Theoretical calculations also show a substantial activation\u0000energy barrier emerges, impeding oxygen infiltration into and reaction with\u0000Na2Cl. The remarkable stability was further demonstrated by the experiment that\u0000Na2Cl crystals on rGO membranes remain almost intact even after prolonged\u0000exposure to a pure oxygen atmosphere for 9 days. The discovered SDIET mechanism\u0000presents a significant leap in stabilizing chemically active substances\u0000harboring active valence electrons under ambient conditions. Its implications\u0000transcend unconventional stoichiometric compounds, encompassing main group and\u0000transition element compounds, potentially influencing various scientific\u0000disciplines.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francisca Sagredo, Stephen E. Gant, Guy Ohad, Jonah B. Haber, Marina R. Filip, Leeor Kronik, Jeffrey B. Neaton
Halide double perovskites are a chemically-diverse and growing class of compound semiconductors that are promising for optoelectronic applications. However, the prediction of their fundamental gaps and optical properties with density functional theory (DFT) and {it ab initio} many-body perturbation theory has been a significant challenge. Recently, a nonempirical Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has been shown to accurately produce the fundamental band gaps of a wide set of semiconductors and insulators, including lead halide perovskites. Here we apply the WOT-SRSH functional to five halide double perovskites, and compare the results with those obtained from other known functionals and previous $GW$ calculations. We also use the approach as a starting point for $GW$ calculations and we compute the band structures and optical absorption spectrum for Cstextsubscript{2}Ag{Bi}Brtextsubscript{6}, using both time-dependent DFT and the $GW$-Bethe-Salpeter equation approach. We show that the WOT-SRSH functional leads to accurate fundamental and optical band gaps, as well as optical absorption spectra, consistent with spectroscopic measurements, thereby establishing WOT-SRSH as a viable method for the accurate prediction of optoelectronic properties of halide double perovskites.
{"title":"Electronic structure and optical properties of halide double perovskites from a Wannier-localized optimally-tuned screened range-separated hybrid functional","authors":"Francisca Sagredo, Stephen E. Gant, Guy Ohad, Jonah B. Haber, Marina R. Filip, Leeor Kronik, Jeffrey B. Neaton","doi":"arxiv-2408.04115","DOIUrl":"https://doi.org/arxiv-2408.04115","url":null,"abstract":"Halide double perovskites are a chemically-diverse and growing class of\u0000compound semiconductors that are promising for optoelectronic applications.\u0000However, the prediction of their fundamental gaps and optical properties with\u0000density functional theory (DFT) and {it ab initio} many-body perturbation\u0000theory has been a significant challenge. Recently, a nonempirical\u0000Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH)\u0000functional has been shown to accurately produce the fundamental band gaps of a\u0000wide set of semiconductors and insulators, including lead halide perovskites.\u0000Here we apply the WOT-SRSH functional to five halide double perovskites, and\u0000compare the results with those obtained from other known functionals and\u0000previous $GW$ calculations. We also use the approach as a starting point for\u0000$GW$ calculations and we compute the band structures and optical absorption\u0000spectrum for Cstextsubscript{2}Ag{Bi}Brtextsubscript{6}, using both\u0000time-dependent DFT and the $GW$-Bethe-Salpeter equation approach. We show that\u0000the WOT-SRSH functional leads to accurate fundamental and optical band gaps, as\u0000well as optical absorption spectra, consistent with spectroscopic measurements,\u0000thereby establishing WOT-SRSH as a viable method for the accurate prediction of\u0000optoelectronic properties of halide double perovskites.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present an implementation of the quantum mechanics/molecular mechanics (QM/MM) method for periodic systems using GPU accelerated QM methods, a distributed multipole formulation of the electrostatics, and a pseudo-bond treatment of the QM/MM boundary. We demonstrate that our method has well-controlled errors, stable self-consistent QM convergence, and energy-conserving dynamics. We further describe an application to the catalytic kinetics of chorismate mutase. Using an accurate hybrid functional reparametrized to coupled cluster energetics, our QM/MM simulations highlight the sensitivity in the calculated rate to the choice of quantum method, quantum region selection, and local protein conformation. Our work is provided through the open-source textsc{PySCF} package using acceleration from the textsc{GPU4PySCF} module.
{"title":"Accurate QM/MM Molecular Dynamics for Periodic Systems in textsc{GPU4PySCF} with Applications to Enzyme Catalysis","authors":"Chenghan Li, Garnet Kin-Lic Chan","doi":"arxiv-2408.03273","DOIUrl":"https://doi.org/arxiv-2408.03273","url":null,"abstract":"We present an implementation of the quantum mechanics/molecular mechanics\u0000(QM/MM) method for periodic systems using GPU accelerated QM methods, a\u0000distributed multipole formulation of the electrostatics, and a pseudo-bond\u0000treatment of the QM/MM boundary. We demonstrate that our method has\u0000well-controlled errors, stable self-consistent QM convergence, and\u0000energy-conserving dynamics. We further describe an application to the catalytic\u0000kinetics of chorismate mutase. Using an accurate hybrid functional\u0000reparametrized to coupled cluster energetics, our QM/MM simulations highlight\u0000the sensitivity in the calculated rate to the choice of quantum method, quantum\u0000region selection, and local protein conformation. Our work is provided through\u0000the open-source textsc{PySCF} package using acceleration from the\u0000textsc{GPU4PySCF} module.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Giovanni Garberoglio, Allan H. Harvey, Jakub Lang, Michal Przybytek, Michal Lesiuk, Bogumil Jeziorski
We develop a surface for the electric dipole moment of three interacting helium atoms and use it, together with state-of-the-art potential and polarizability surfaces, to compute the third dielectric virial coefficient, $C_varepsilon$, for both $^4$He and $^3$He isotopes. Our results agree with previously published data computed using an approximated form for the three-body polarizability, and are extended to the low-temperature regime by including exchange effects. Additionally, the uncertainty of $C_varepsilon$ is rigorously determined for the first time by propagating the uncertainties of the potential and polarizability surfaces; this uncertainty is much larger than the contribution from the dipole-moment surface to $C_varepsilon$. Our results compare reasonably well with the limited experimental data. The first-principles values of $C_epsilon$ computed in this work will enhance the accuracy of primary temperature and pressure metrology based on measurements of the dielectric constant of helium.
{"title":"Path-integral calculation of the third dielectric virial coefficient of helium based on ab initio three-body polarizability and dipole surfaces","authors":"Giovanni Garberoglio, Allan H. Harvey, Jakub Lang, Michal Przybytek, Michal Lesiuk, Bogumil Jeziorski","doi":"arxiv-2408.03176","DOIUrl":"https://doi.org/arxiv-2408.03176","url":null,"abstract":"We develop a surface for the electric dipole moment of three interacting\u0000helium atoms and use it, together with state-of-the-art potential and\u0000polarizability surfaces, to compute the third dielectric virial coefficient,\u0000$C_varepsilon$, for both $^4$He and $^3$He isotopes. Our results agree with\u0000previously published data computed using an approximated form for the\u0000three-body polarizability, and are extended to the low-temperature regime by\u0000including exchange effects. Additionally, the uncertainty of $C_varepsilon$ is\u0000rigorously determined for the first time by propagating the uncertainties of\u0000the potential and polarizability surfaces; this uncertainty is much larger than\u0000the contribution from the dipole-moment surface to $C_varepsilon$. Our results\u0000compare reasonably well with the limited experimental data. The\u0000first-principles values of $C_epsilon$ computed in this work will enhance the\u0000accuracy of primary temperature and pressure metrology based on measurements of\u0000the dielectric constant of helium.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A recent report by Barik et al. [Nature Chemistry 14, 1098, 2022] on ambient-light-induced intermolecular Coulombic decay (ICD) in unbound pyridine monomers proposes the formation of a pyridine cation via intermolecular Coulombic decay following a three-body association/collision, wherein all the three pyridine molecules are in the excited state. The collision-free conditions of the free-jet expansion, an abysmally low probability of finding three independently excited pyridine molecules in the vicinity of each other, and extremely low excited state lifetimes negate the possibility of ICD in unbound pyridine monomers. An alternate mechanism, wherein the pyridine monomer cation originates from the dissociative ionization of pyridine dimers following a three-photon absorption process, based on the translational energy measurements of pyridine cation is proposed.
{"title":"On Ambient-light-induced intermolecular Coulombic decay in unbound pyridine monomers","authors":"Shaivi Kesari, Amol Tagad, G. Naresh Patwari","doi":"arxiv-2408.02981","DOIUrl":"https://doi.org/arxiv-2408.02981","url":null,"abstract":"A recent report by Barik et al. [Nature Chemistry 14, 1098, 2022] on\u0000ambient-light-induced intermolecular Coulombic decay (ICD) in unbound pyridine\u0000monomers proposes the formation of a pyridine cation via intermolecular\u0000Coulombic decay following a three-body association/collision, wherein all the\u0000three pyridine molecules are in the excited state. The collision-free\u0000conditions of the free-jet expansion, an abysmally low probability of finding\u0000three independently excited pyridine molecules in the vicinity of each other,\u0000and extremely low excited state lifetimes negate the possibility of ICD in\u0000unbound pyridine monomers. An alternate mechanism, wherein the pyridine monomer\u0000cation originates from the dissociative ionization of pyridine dimers following\u0000a three-photon absorption process, based on the translational energy\u0000measurements of pyridine cation is proposed.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"195 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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