arXiv - PHYS - Atomic and Molecular Clusters最新文献

Types of Size-Dependent Melting in Fe Nanoclusters: a Molecular Dynamics Study 铁纳米团簇中随尺寸变化的熔化类型：分子动力学研究

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-09-03 DOI: arxiv-2409.02293

Louis E. S. Hoffenberg, Alexander Khrabry, Yuri Barsukov, Igor D. Kaganovich, David B. Graves

{"title":"Types of Size-Dependent Melting in Fe Nanoclusters: a Molecular Dynamics Study","authors":"Louis E. S. Hoffenberg, Alexander Khrabry, Yuri Barsukov, Igor D. Kaganovich, David B. Graves","doi":"arxiv-2409.02293","DOIUrl":"https://doi.org/arxiv-2409.02293","url":null,"abstract":"Metallic nanoclusters are of interest in many fields because of their\u0000size-dependent catalytic activity. This activity can, in part, be influenced by\u0000their melting properties. In this work, the melting phase transitions of\u0000$Fe_{n}$ nanoclusters with $n leq 100$ atoms were investigated using classical\u0000many-body molecular dynamics simulations. Adding a single atom to many cluster\u0000sizes induced strong variations in melting point ($T_{melt}$), latent heat of\u0000melting ($Delta H_{melt}$), and onset temperature of isomerization\u0000($T_{iso}$). Clusters with size-dependent melting behavior were classified into\u00003 distinct cluster types: closed-shell, near-closed-shell, and\u0000far-from-closed-shell clusters. First-order-like phase transitions were\u0000observed only for cluster sizes with particularly symmetric closed shells and\u0000near-closed shells with up to a few missing or extra atoms. Near-closed-shell\u0000clusters had very low $T_{iso}$ relative to their $T_{melt}$.\u0000Far-from-closed-shell clusters exhibited second-order-like phase transitions.\u0000Variations in the melting and isomerization behavior of neighboring cluster\u0000sizes may have implications for catalytic systems such as the growth of\u0000single-wall carbon nanotubes.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221972","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}

引用次数: 0

How to manipulate nanoparticle morphology with vacancies 如何利用空位操纵纳米粒子形态

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-09-02 DOI: arxiv-2409.01254

Ilia SmirnovUniversity of Warsaw, Warsaw, Poland, Zbigniew KaszkurInstitute of Physical Chemistry, Warsaw, Poland, Riccardo FerrandoUniversity of Genoa, Genoa, Italy

引用次数: 0

Collective states of α-sexithiophene chains inside boron nitride nanotubes 氮化硼纳米管内 α-噻吩链的集合态

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-08-28 DOI: arxiv-2408.15885

Sabrina Juergensen, Jean-Baptiste Marceau, Chantal Mueller, Eduardo B. Barros, Patryk Kusch, Antonio Setaro, Etienne Gaufrès, Stephanie Reich

{"title":"Collective states of α-sexithiophene chains inside boron nitride nanotubes","authors":"Sabrina Juergensen, Jean-Baptiste Marceau, Chantal Mueller, Eduardo B. Barros, Patryk Kusch, Antonio Setaro, Etienne Gaufrès, Stephanie Reich","doi":"arxiv-2408.15885","DOIUrl":"https://doi.org/arxiv-2408.15885","url":null,"abstract":"Nanotubes align molecules into one dimensional chains creating collective\u0000states through the coupling of the molecular transition dipole moments. These\u0000collective excitations have strong fluorescence, narrow bandwidth, and shifted\u0000emission/absorption energies. We study the optical properties of\u0000{alpha}-sexithiophene chains in boron nitride nanotubes by combining\u0000fluorescence with far- and near-field absorption spectroscopy. The inner\u0000nanotube diameter determines the number of encapsulated molecular chains. A\u0000single chain of {alpha}-sexithiophene molecules has an optical absorption and\u0000emission spectrum that is red-shifted by almost 300 meV compared to the monomer\u0000emission, which is much larger than expected from dipole-dipole coupling. The\u0000collective state splits into excitation and emission channels with a Stokes\u0000shift of 200 meV for chains with two or more files. Our study emphasises the\u0000formation of a delocalized collective state through Coulomb coupling of the\u0000transition moments that shows a remarkable tuneability in transition energy.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227545","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}

引用次数: 0

Accelerated structure-stability energy-free calculator 加速结构稳定性无能量计算器

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-08-26 DOI: arxiv-2408.14577

Alexandre Boucher, Cameron Beevers, Bertrand Gauthier, Alberto Roldan

{"title":"Accelerated structure-stability energy-free calculator","authors":"Alexandre Boucher, Cameron Beevers, Bertrand Gauthier, Alberto Roldan","doi":"arxiv-2408.14577","DOIUrl":"https://doi.org/arxiv-2408.14577","url":null,"abstract":"Computational modeling is an integral part of catalysis research. With it,\u0000new methodologies are being developed and implemented to improve the accuracy\u0000of simulations while reducing the computational cost. In particular, specific\u0000machine-learning techniques have been applied to build interatomic potential\u0000from ab initio results. Here, We report an energy-free machine-learning\u0000calculator that combines three individually trained neural networks to predict\u0000the energy and atomic forces of particulate matter. Three structures were\u0000investigated: a monometallic nanoparticle, a bimetallic nanoalloy, and a\u0000supported metal crystallites. Atomic energies were predicted via a graph neural\u0000network, leading to a mean absolute error (MAE) within 0.004 eV from Density\u0000Functional Theory (DFT) calculations. The task of predicting atomic forces was\u0000split over two feedforward networks, one predicting the force's norm and\u0000another its direction. The force prediction resulted in a MAE within 0.080 eV/A\u0000against DFT results. The interpretability of the graph neural network\u0000predictions was demonstrated by underlying the physics of the monometallic\u0000particle in the form of cohesion energy.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221974","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}

引用次数: 0

Structures and infrared spectroscopy of Au$_{10}$ cluster at different temperatures 不同温度下 Au$_{10}$ 簇的结构和红外光谱分析

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-08-24 DOI: arxiv-2408.13451

Francisco Eduardo Rojas-González, Jorge Padilla-Alvarez, César Castillo-Quevedo, Rajagopal Dashinamoorthy Eithiraj, Jose Luis Cabellos

{"title":"Structures and infrared spectroscopy of Au$_{10}$ cluster at different temperatures","authors":"Francisco Eduardo Rojas-González, Jorge Padilla-Alvarez, César Castillo-Quevedo, Rajagopal Dashinamoorthy Eithiraj, Jose Luis Cabellos","doi":"arxiv-2408.13451","DOIUrl":"https://doi.org/arxiv-2408.13451","url":null,"abstract":"Understanding the properties of Au$_{10}$ clusters entails identifying the\u0000lowest energy structure at cold and warm temperatures. While functional\u0000materials operate at finite temperatures, energy computations using density\u0000functional theory are typically performed at zero temperature, resulting in\u0000unexplored properties. Our study undertook an exploration of the potential and\u0000free energy surface of the neutral Au$_{10}$ nanocluster at finite temperatures\u0000by employing a genetic algorithm combined with density functional theory and\u0000nanothermodynamics. We computed the thermal population and infrared Boltzmann\u0000spectrum at a finite temperature, aligning the results with validated\u0000experimental data. The Zero-Order Regular Approximation (ZORA) gave\u0000consideration to relativistic effects, and dispersion was incorporated using\u0000Grimme's dispersion D3BJ with Becke-Johnson damping. Moreover,\u0000nanothermodynamics was utilized to account for temperature contributions. The\u0000computed thermal population strongly supports the dominance of the 2D elongated\u0000hexagon configuration within a temperature range of 50 to 800 K. Importantly,\u0000at a temperature of 100 K, the calculated IR Boltzmann spectrum aligns with the\u0000experimental IR spectrum. Lastly, the chemical bonding analysis on the lowest\u0000energy structure indicates a closed-shell Au-Au interaction with a weak or\u0000partially covalent character.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221975","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}

引用次数: 0

Reactive molecular dynamics simulations of micrometeoroid bombardment for space weathering of asteroid (162173) Ryugu 微流星体轰击小行星（162173）龙宫的空间风化作用的反应分子动力学模拟

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-08-20 DOI: arxiv-2408.10959

Daigo Shoji

{"title":"Reactive molecular dynamics simulations of micrometeoroid bombardment for space weathering of asteroid (162173) Ryugu","authors":"Daigo Shoji","doi":"arxiv-2408.10959","DOIUrl":"https://doi.org/arxiv-2408.10959","url":null,"abstract":"Remote sensing observations by Hayabusa2 and laboratory measurements have\u0000revealed that the phyllosilicates on asteroid (162173) Ryugu are\u0000dehydrated/dehydroxylated due to space weathering. Reactive molecular dynamics\u0000simulations were performed to evaluate the magnitude of the dehydroxylation of\u0000Mg-rich serpentine by micrometeoroid impacts. When micrometeoroids were not\u0000coupled with interplanetary magnetic fields, serpentine could be dehydroxylated\u0000by micrometeoroids as small as 2 nm in size. In particular, ~200 O-H bonds\u0000dissociated when the meteoroids were derived from cometary activity (the impact\u0000velocity was ~20 km s$^{-1}$). When nano-sized dust particles were accelerated\u0000to ~300 km s$^{-1}$ by the magnetic fields of solar wind plasma, the number of\u0000dissociated O-H bonds increased by one order of magnitude. Consequently even 1\u0000nm-sized dust particles can contribute to the space weathering of Ryugu. In all\u0000cases, Si-OH, H2O, and free OH were generated from the hydroxyls initially\u0000connected to Mg, which could partially offset dehydration. Despite the\u0000limitations of our computational resources, which restricted the simulation\u0000time scale to 1 ps, reactive molecular dynamic simulations demonstrated that\u0000micrometeoroid bombardment could influence the space weathering of asteroids.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221976","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}

引用次数: 0

Electronic State Chromatography of Lutetium Cations 镥阳离子的电子态色谱法

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-07-15 DOI: arxiv-2407.10851

Biswajit Jana, EunKang Kim, Aayush Arya, Elisa Romero Romero, Elisabeth Rickert, Harry Ramanantoanina, Sebastian Raeder, Michael Block, Mustapha Laatiaoui

{"title":"Electronic State Chromatography of Lutetium Cations","authors":"Biswajit Jana, EunKang Kim, Aayush Arya, Elisa Romero Romero, Elisabeth Rickert, Harry Ramanantoanina, Sebastian Raeder, Michael Block, Mustapha Laatiaoui","doi":"arxiv-2407.10851","DOIUrl":"https://doi.org/arxiv-2407.10851","url":null,"abstract":"Relativistic effects strongly influence the electronic structures of the\u0000heaviest elements, thereby shaping their chemical and physical properties.\u0000Studying ion mobility within a noble gas environment reveals how the\u0000ion-neutral interactions depend on the ion's electronic configurations, thus\u0000providing an avenue for exploring these effects. An ion mobility spectrometer\u0000with a cryogenic drift tube was developed to precisely measure the low-field\u0000reduced mobility of heavy lanthanide and actinide cations. The apparatus was\u0000characterized by optimizing the bunching operation of ions with a miniature RF\u0000coulomb buncher and evaluating the chromatography performance of the drift tube\u0000operated with helium buffer gas at a temperature of 298K. Systematic ion\u0000mobility measurements of lutetium cations (Lu$^{+}$) drifting in helium gas\u0000were carried out as a case study. The electronic state chromatography of\u0000Lu$^{+}$ has been demonstrated. The low-field reduced ion mobility for the\u0000ground and lowest meta-stable state of Lu$^{+}$ have been examined. In\u0000addition, the variation of both states' reduced mobility and the quenching of\u0000meta-stable population has been investigated under different reduced electric\u0000fields ($E/n_0$), the ratio of an electric field to neutral gas number density.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141718809","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}

引用次数: 0

Cold molecular ions via autoionization below the dissociation limit 低于解离极限的自电离冷分子离子

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-06-05 DOI: arxiv-2406.03160

Sascha Schaller, Johannes Seifert, Giacomo Valtolina, André Fielicke, Boris G. Sartakov, Gerard Meijer

引用次数: 0

Alkaline earth metal mediated inter-molecular magnetism in perfluorocubane dimers and chains 碱土金属介导的全氟丁烷二聚体和链的分子间磁性

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-05-20 DOI: arxiv-2405.12060

Zhuohang Li, Cong Wang, Linwei Zhou, Yurou Guan, Linlu Wu, Jiaqi Dai, Wei Ji

{"title":"Alkaline earth metal mediated inter-molecular magnetism in perfluorocubane dimers and chains","authors":"Zhuohang Li, Cong Wang, Linwei Zhou, Yurou Guan, Linlu Wu, Jiaqi Dai, Wei Ji","doi":"arxiv-2405.12060","DOIUrl":"https://doi.org/arxiv-2405.12060","url":null,"abstract":"Perfluorocubane ($C_8F_8$) was successfully synthesized and found to accept\u0000and store electrons in its internal cubic cavity to form magnetic moments.\u0000However their inter-molecule spin-exchange coupling mechanism is yet to be\u0000revealed. In this study, we found the inter-molecule magnetic groundstates of\u0000$C_8F_8$ dimer and one-dimensional (1D) chain are tunable from\u0000antiferromagnetic (AFM) to ferromagnetic (FM) by stacking orders and alkaline\u0000earth metals intercalation using first-principle calculations. The\u0000inter-molecule couplings are dominated by noncovalent halogen $C-F...C_4$\u0000interactions. Stacking orders of dimers can regulate the relative position of\u0000the lone pairs and $sigma-holes$ at the molecular interface and thus the\u0000magnetic groundstates. Alkaline earth metals M (M = Na, Mg) intercalations\u0000could form $C_4-M-C_4$ bonds and lead to FM direct exchange at the\u0000inter-molecule region. An unpaired electron donated by the intercalated atoms\u0000or electron doping can result in a local magnetic moment in dimers, exhibiting\u0000an on-off switching by the odd-even number of electron filling. Novel\u0000electronic properties such as spin gapless semiconductor and charge density\u0000wave (CDW) states emerge when $C_8F_8$ molecules self-assemble with\u0000intercalated atoms to form 1D chains. These findings manifest the roles of\u0000stacking and intercalation in modifying intermolecular magnetism and the\u0000revealed halogen bond-dominated exchange mechanisms are paramount additions to\u0000those previously established non-covalent couplings.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"2014 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148382","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}

引用次数: 0

Theoretical investigation on the optical absorption spectra in cyclo[n]carbons (n=10, 14, 18) 环[n]碳（n=10、14、18）光学吸收光谱的理论研究

arXiv - PHYS - Atomic and Molecular Clusters Pub Date : 2024-03-29 DOI: arxiv-2403.19952

Xuhai Hong, Lang Su, Jie Li

引用次数: 0