Feng Wang, Wangqiang Shen, Yuan Shui, Jun Chen, Huaiqiang Wang, Rui Wang, Yuyuan Qin, Xuefeng Wang, Jianguo Wan, Minhao Zhang, Xing Lu, Tao Yang, Fengqi Song
Single-atom magnetism switching is a key technique towards the ultimate data storage density of computer hard disks and has been conceptually realized by leveraging the spin bistability of a magnetic atom under a scanning tunnelling microscope. However, it has rarely been applied to solid-state transistors, an advancement that would be highly desirable for enabling various applications. Here, we demonstrate realization of the electrically controlled Zeeman effect in Dy@C84 single-molecule transistors, thus revealing a transition in the magnetic moment from 3.8 {mu}B to 5.1 {mu}B for the ground-state GN at an electric field strength of 3-10 MV/cm. The consequent magnetoresistance significantly increases from 600% to 1100% at the resonant tunneling point. Density functional theory calculations further corroborate our realization of nonvolatile switching of single-atom magnetism, and the switching stability emanates from an energy barrier of 92 meV for atomic relaxation. These results highlight the potential of using endohedral metallofullerenes for high-temperature, high-stability, high-speed, and compact single-atom magnetic data storage.
{"title":"Electrically controlled nonvolatile switching of single-atom magnetism in a Dy@C84 single-molecule transistor","authors":"Feng Wang, Wangqiang Shen, Yuan Shui, Jun Chen, Huaiqiang Wang, Rui Wang, Yuyuan Qin, Xuefeng Wang, Jianguo Wan, Minhao Zhang, Xing Lu, Tao Yang, Fengqi Song","doi":"arxiv-2403.11137","DOIUrl":"https://doi.org/arxiv-2403.11137","url":null,"abstract":"Single-atom magnetism switching is a key technique towards the ultimate data\u0000storage density of computer hard disks and has been conceptually realized by\u0000leveraging the spin bistability of a magnetic atom under a scanning tunnelling\u0000microscope. However, it has rarely been applied to solid-state transistors, an\u0000advancement that would be highly desirable for enabling various applications.\u0000Here, we demonstrate realization of the electrically controlled Zeeman effect\u0000in Dy@C84 single-molecule transistors, thus revealing a transition in the\u0000magnetic moment from 3.8 {mu}B to 5.1 {mu}B for the ground-state GN at an\u0000electric field strength of 3-10 MV/cm. The consequent magnetoresistance\u0000significantly increases from 600% to 1100% at the resonant tunneling point.\u0000Density functional theory calculations further corroborate our realization of\u0000nonvolatile switching of single-atom magnetism, and the switching stability\u0000emanates from an energy barrier of 92 meV for atomic relaxation. These results\u0000highlight the potential of using endohedral metallofullerenes for\u0000high-temperature, high-stability, high-speed, and compact single-atom magnetic\u0000data storage.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"162 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140170141","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}
The advancement of liquid phase electron beam induced deposition has enabled an effective direct-write approach for functional nanostructure synthesis with the possibility of three-dimensional control of morphology. For formation of a metallic solid phase, the process employs ambient temperature, beam-guided, electrochemical reduction of precursor cations resulting in rapid formation of structures, but with challenges for retention of resolution achievable via slower electron beam approaches. The possibility of spatial control of redox pathways via the use of water-ammonia solvents has opened new avenues for improved nanostructure resolution without sacrificing the growth rate. We find that ammonia concentration locally modulates reaction kinetics, altering the balance between reducing and oxidizing species, leading to distinct deposition outcomes. The key effect is an 'electrochemical lensing', achieved at an optimum ammonia concentration, in which a tightly confined and highly reducing environment is created locally to enable high resolution, rapid beam-directed nanostructure growth. We demonstrate this unique approach to high resolution synthesis through a combination of analysis and experiment.
{"title":"Electrochemical Lensing for High Resolution Nanostructure Synthesis","authors":"Auwais Ahmed, Peter A. Kottke, Andrei G. Fedorov","doi":"arxiv-2403.06010","DOIUrl":"https://doi.org/arxiv-2403.06010","url":null,"abstract":"The advancement of liquid phase electron beam induced deposition has enabled\u0000an effective direct-write approach for functional nanostructure synthesis with\u0000the possibility of three-dimensional control of morphology. For formation of a\u0000metallic solid phase, the process employs ambient temperature, beam-guided,\u0000electrochemical reduction of precursor cations resulting in rapid formation of\u0000structures, but with challenges for retention of resolution achievable via\u0000slower electron beam approaches. The possibility of spatial control of redox\u0000pathways via the use of water-ammonia solvents has opened new avenues for\u0000improved nanostructure resolution without sacrificing the growth rate. We find\u0000that ammonia concentration locally modulates reaction kinetics, altering the\u0000balance between reducing and oxidizing species, leading to distinct deposition\u0000outcomes. The key effect is an 'electrochemical lensing', achieved at an\u0000optimum ammonia concentration, in which a tightly confined and highly reducing\u0000environment is created locally to enable high resolution, rapid beam-directed\u0000nanostructure growth. We demonstrate this unique approach to high resolution\u0000synthesis through a combination of analysis and experiment.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140105488","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}
Matteo De Tullio, Giovanni Noviinverardi, Jonathan Houard, Marc Ropitaux, Ivan Blum, Francesco Carnovale, Gianluca Lattanzi, Simone Taioli, Gustav Eriksson, Mats Hulander, Martin Andersson, Angela Vella, Tommaso Morresi
In this study, we use THz-assisted atom probe tomography (APT) to analyse silica matrices used to encapsulate biomolecules. This technique provides the chemical composition and 3D structure without significantly heating the biosample, which is crucial for studying soft organic molecules such as proteins. Our results show that THz pulses and a positive static field trigger controlled evaporation of silica matrices, enabling 4D imaging with chemical sensitivity comparable to UV laser-assisted APT. To support the interpretation of these experimental results, we devise a computational model based on time-dependent density functional theory to describe the interaction between silica matrices and THz radiation. This model captures the nonlinear dynamics driven by THz-pulses and the interplay between the THz source and the static electric field in real time. This interdisciplinary approach expands the capabilities of APT and holds promise for other THz-based analyses offering new insights into material dynamics in complex biological environments.
{"title":"THz-assisted microscopy of silica matrix for biological materials encapsulation: a theoretical and experimental study","authors":"Matteo De Tullio, Giovanni Noviinverardi, Jonathan Houard, Marc Ropitaux, Ivan Blum, Francesco Carnovale, Gianluca Lattanzi, Simone Taioli, Gustav Eriksson, Mats Hulander, Martin Andersson, Angela Vella, Tommaso Morresi","doi":"arxiv-2403.04470","DOIUrl":"https://doi.org/arxiv-2403.04470","url":null,"abstract":"In this study, we use THz-assisted atom probe tomography (APT) to analyse\u0000silica matrices used to encapsulate biomolecules. This technique provides the\u0000chemical composition and 3D structure without significantly heating the\u0000biosample, which is crucial for studying soft organic molecules such as\u0000proteins. Our results show that THz pulses and a positive static field trigger\u0000controlled evaporation of silica matrices, enabling 4D imaging with chemical\u0000sensitivity comparable to UV laser-assisted APT. To support the interpretation\u0000of these experimental results, we devise a computational model based on\u0000time-dependent density functional theory to describe the interaction between\u0000silica matrices and THz radiation. This model captures the nonlinear dynamics\u0000driven by THz-pulses and the interplay between the THz source and the static\u0000electric field in real time. This interdisciplinary approach expands the\u0000capabilities of APT and holds promise for other THz-based analyses offering new\u0000insights into material dynamics in complex biological environments.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140073858","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}
The phase transition of confined fluids in mesoporous materials deviates from that of bulk fluids due to the former's interactions with the surrounding heterogeneous structure. For example, metal-organic frameworks (MOFs) create a strong heterogeneous field, so adsorbed fluids in MOFs have atypical phase characteristics such as capillary condensation and higher-order phase transitions. These characteristics are modeled by decoupling the host-guest and guest-guest interactions as a many-body problem in the presence of an external nonuniform field. To solve the three-dimensional Ising model, we use mean-field theory to approximate the guest-guest interactions and Mayer's (f)-functions to describe the host-guest interactions in a unit cell. Later, using Hill's theory of nanothermodynamics, we define differential and integral thermodynamic functions to describe confined fluids. These integral properties are then used to understand the phase transition in confined fluids. The investigation reveals a distinct behavior where fluids confined in larger pores undergo a discontinuous (first-order) phase transition, whereas those confined in smaller pores undergo a continuous (higher-order) phase transition. Furthermore, the results indicate that the free-energy barrier for phase transitions is lower in confined fluids than in bulk fluids, which helps explain the lower condensation pressure relative to the bulk saturation pressure. Finally, the integral thermodynamic functions are succinctly presented in the form of a phase diagram, marking an initial step toward a more practical approach for understanding the phase behavior of confined fluids.
{"title":"Statistical modeling of equilibrium phase transition in confined fluids","authors":"Gunjan Auti, Soumyadeep Paul, Shohei Chiashi, Hirofumi Daiguji","doi":"arxiv-2403.03162","DOIUrl":"https://doi.org/arxiv-2403.03162","url":null,"abstract":"The phase transition of confined fluids in mesoporous materials deviates from\u0000that of bulk fluids due to the former's interactions with the surrounding\u0000heterogeneous structure. For example, metal-organic frameworks (MOFs) create a\u0000strong heterogeneous field, so adsorbed fluids in MOFs have atypical phase\u0000characteristics such as capillary condensation and higher-order phase\u0000transitions. These characteristics are modeled by decoupling the host-guest and\u0000guest-guest interactions as a many-body problem in the presence of an external\u0000nonuniform field. To solve the three-dimensional Ising model, we use mean-field\u0000theory to approximate the guest-guest interactions and Mayer's (f)-functions to\u0000describe the host-guest interactions in a unit cell. Later, using Hill's theory\u0000of nanothermodynamics, we define differential and integral thermodynamic\u0000functions to describe confined fluids. These integral properties are then used\u0000to understand the phase transition in confined fluids. The investigation\u0000reveals a distinct behavior where fluids confined in larger pores undergo a\u0000discontinuous (first-order) phase transition, whereas those confined in smaller\u0000pores undergo a continuous (higher-order) phase transition. Furthermore, the\u0000results indicate that the free-energy barrier for phase transitions is lower in\u0000confined fluids than in bulk fluids, which helps explain the lower condensation\u0000pressure relative to the bulk saturation pressure. Finally, the integral\u0000thermodynamic functions are succinctly presented in the form of a phase\u0000diagram, marking an initial step toward a more practical approach for\u0000understanding the phase behavior of confined fluids.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"272 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140046460","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}
Manuel Iñarrea, J. Pablo Salas, R. González-Férez, P. Schmelcher
We explore the energy transfer dynamics in an array of two chains of identical rigid interacting dipoles. A crossover between two different ground state (GS) equilibrium configurations is observed with varying distance between the two chains of the array. Linearizing around the GS configurations, we verify that interactions up to third nearest neighbors should be accounted for accurately describe the resulting dynamics. Starting with one of the GS, we excite the system by supplying it with an excess energy DK located initially on one of the dipoles. We study the time evolution of the array for different values of the system parameters b and DK. Our focus is hereby on two features of the energy propagation: the redistribution of the excess energy DK among the two chains and the energy localization along each chain. For typical parameter values, the array of dipoles reaches both the equipartition between the chains and the thermal equilibrium from the early stages of the time evolution. Nevertheless, there is a region in parameter space (b,DK) where even up to the long computation time of this study, the array does neither reach energy equipartition nor thermalization between chains. This fact is due to the existence of persistent chaotic breathers.
{"title":"Equilibria and Dynamics of two coupled chains of interacting dipoles","authors":"Manuel Iñarrea, J. Pablo Salas, R. González-Férez, P. Schmelcher","doi":"arxiv-2402.17471","DOIUrl":"https://doi.org/arxiv-2402.17471","url":null,"abstract":"We explore the energy transfer dynamics in an array of two chains of\u0000identical rigid interacting dipoles. A crossover between two different ground\u0000state (GS) equilibrium configurations is observed with varying distance between\u0000the two chains of the array. Linearizing around the GS configurations, we\u0000verify that interactions up to third nearest neighbors should be accounted for\u0000accurately describe the resulting dynamics. Starting with one of the GS, we\u0000excite the system by supplying it with an excess energy DK located initially on\u0000one of the dipoles. We study the time evolution of the array for different\u0000values of the system parameters b and DK. Our focus is hereby on two features\u0000of the energy propagation: the redistribution of the excess energy DK among the\u0000two chains and the energy localization along each chain. For typical parameter\u0000values, the array of dipoles reaches both the equipartition between the chains\u0000and the thermal equilibrium from the early stages of the time evolution.\u0000Nevertheless, there is a region in parameter space (b,DK) where even up to the\u0000long computation time of this study, the array does neither reach energy\u0000equipartition nor thermalization between chains. This fact is due to the\u0000existence of persistent chaotic breathers.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003400","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. J. Barclay, A. R. W. McKellar, N. Moazzen-Ahmadi
The O-D stretch fundamental region of the deuterated water dimer, (D2O)2, is further studied using a pulsed supersonic slit jet and a tunable optical parametric oscillator infrared source. The previously unobserved acceptor symmetric O-D stretch fundamental vibration is detected, with Ka = 0 <-- 0 and 1 <-- 0 sub-bands at about 2669 and 2674 cm-1, respectively. Analysis indicates that the various water dimer tunneling splittings generally decrease in the excited vibrational state, similar to the three other previously observed O-D stretch fundamentals. Two new (D2O)2 combination bands are observed, giving information on intermolecular vibrations in the excited O-D stretch states. The likely vibrational assignments for these and a previously observed combination band are discussed.
{"title":"Spectra of the D2O dimer in the O-D fundamental stretch region: the acceptor symmetric stretch fundamental and new combination bands","authors":"A. J. Barclay, A. R. W. McKellar, N. Moazzen-Ahmadi","doi":"arxiv-2402.14923","DOIUrl":"https://doi.org/arxiv-2402.14923","url":null,"abstract":"The O-D stretch fundamental region of the deuterated water dimer, (D2O)2, is\u0000further studied using a pulsed supersonic slit jet and a tunable optical\u0000parametric oscillator infrared source. The previously unobserved acceptor\u0000symmetric O-D stretch fundamental vibration is detected, with Ka = 0 <-- 0 and\u00001 <-- 0 sub-bands at about 2669 and 2674 cm-1, respectively. Analysis indicates\u0000that the various water dimer tunneling splittings generally decrease in the\u0000excited vibrational state, similar to the three other previously observed O-D\u0000stretch fundamentals. Two new (D2O)2 combination bands are observed, giving\u0000information on intermolecular vibrations in the excited O-D stretch states. The\u0000likely vibrational assignments for these and a previously observed combination\u0000band are discussed.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"2016 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139969425","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}
Artificial molecular rotors and motors hold great promise for functional nanomachines, but constructing diatomic rotors, crucial for these machines, is challenging due to surface constraints and limited chemical design. Here we report the construction of diatomic Cr-Cs and Fe-Cs rotors where a Cr or Fe atom revolves around a Cs atom at the Sb surface of the newly-discovered kagome superconductor CsV3Sb5. The rotation rate is controlled by bias voltage between the rotor and scanning tunneling microscope (STM) tip. The spatial distribution of rates exhibits C2 symmetry, might linked to the symmetry-breaking charge orders of CsV3Sb5. We have expanded rotor construction to include different transition metals (Cr, Fe, V) and alkali metals (Cs, K). Remarkably, designed configurations of rotors are achieved through STM manipulation. Rotor orbits and quantum states are precisely controlled by tunning inter-rotor distance. Our findings establish a novel platform for the atomically precise fabrication of atomic motors on symmetry-breaking quantum materials, paving the way for advanced nanoscale devices.
{"title":"Formation and manipulation of diatomic rotors at the symmetry-breaking surfaces of kagome superconductors","authors":"Zihao Huang, Xianghe Han, Zhen Zhao, Haitao Yang, Hui Chen, Hong-Jun Gao","doi":"arxiv-2402.11519","DOIUrl":"https://doi.org/arxiv-2402.11519","url":null,"abstract":"Artificial molecular rotors and motors hold great promise for functional\u0000nanomachines, but constructing diatomic rotors, crucial for these machines, is\u0000challenging due to surface constraints and limited chemical design. Here we\u0000report the construction of diatomic Cr-Cs and Fe-Cs rotors where a Cr or Fe\u0000atom revolves around a Cs atom at the Sb surface of the newly-discovered kagome\u0000superconductor CsV3Sb5. The rotation rate is controlled by bias voltage between\u0000the rotor and scanning tunneling microscope (STM) tip. The spatial distribution\u0000of rates exhibits C2 symmetry, might linked to the symmetry-breaking charge\u0000orders of CsV3Sb5. We have expanded rotor construction to include different\u0000transition metals (Cr, Fe, V) and alkali metals (Cs, K). Remarkably, designed\u0000configurations of rotors are achieved through STM manipulation. Rotor orbits\u0000and quantum states are precisely controlled by tunning inter-rotor distance.\u0000Our findings establish a novel platform for the atomically precise fabrication\u0000of atomic motors on symmetry-breaking quantum materials, paving the way for\u0000advanced nanoscale devices.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139928670","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}
Jong Chan Lee, Begüm Rukiye Özer, In Heo, Thomas Schultz
Fragment signals in ordinary mass spectra carry no label to identify their parent molecule. By correlating mass signals with rotational Raman spectra, we created a method to label each ion signal with the spectroscopic fingerprint of its neutral parent molecule. In data for a carbon disulfide molecular cluster beam, we assigned 28 distinct ionization and fragmentation channels based on their mass-correlated rotational fingerprints. Unexpected observations included the formation of energetic S2 and SCCS cationic fragments from the CS2-dimer cluster and a significant CS3 signal, uncorrelated to the dimer. The large number of observed channels revealed a surprising complexity that could only be addressed with correlated spectroscopy and computer-aided correlation analysis.
{"title":"Correlating parent-fragment relationships in cluster photoionization","authors":"Jong Chan Lee, Begüm Rukiye Özer, In Heo, Thomas Schultz","doi":"arxiv-2402.08398","DOIUrl":"https://doi.org/arxiv-2402.08398","url":null,"abstract":"Fragment signals in ordinary mass spectra carry no label to identify their\u0000parent molecule. By correlating mass signals with rotational Raman spectra, we\u0000created a method to label each ion signal with the spectroscopic fingerprint of\u0000its neutral parent molecule. In data for a carbon disulfide molecular cluster\u0000beam, we assigned 28 distinct ionization and fragmentation channels based on\u0000their mass-correlated rotational fingerprints. Unexpected observations included\u0000the formation of energetic S2 and SCCS cationic fragments from the CS2-dimer\u0000cluster and a significant CS3 signal, uncorrelated to the dimer. The large\u0000number of observed channels revealed a surprising complexity that could only be\u0000addressed with correlated spectroscopy and computer-aided correlation analysis.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139772142","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}
Khaled Mosharraf MukutMarquette University, Milwaukee, USA, Anindya GangulyUniversity of Melbourne, Melbourne, Australia, Eirini GoudeliUniversity of Melbourne, Melbourne, Australia, Georgios A. KelesidisRutgers, The State University of New Jersey, Piscataway, USAETH Zurich, Zurich, Switzerland, Somesh P. RoyMarquette University, Milwaukee, USA
Incipient soot particles obtained from a series of reactive molecular dynamics simulations were studied to understand the evolution of physical, chemical, and morphological properties of incipient soot. Reactive molecular dynamics simulations of acetylene pyrolysis were performed using ReaxFF potential at 1350, 1500, 1650, and 1800 K. A total of 3324 incipient soot particles were extracted from the simulations at various stages of development. Features such as the number of carbon and hydrogen atoms, number of ring structures, mass, C/H ratio, radius of gyration, surface area, volume, atomic fractal dimension, and density were calculated for each particle. The calculated values of density and C/H ratio matched well with experimental values reported in the literature. Based on the calculated features, the particles were classified in two types: type 1 and type 2 particles. It was found that type 1 particles show significant morphological evolution while type 2 particles undergo chemical restructuring without any significant morphological change. The particle volume was found to be well-correlated with the number of carbon atoms in both type 1 and type 2 particle, whereas surface area was found to be correlated with the number of carbon atoms only for type 1 particles. A correlation matrix comparing the level of correlation between any two features for both type 1 and type 2 particle was created. Finally, based on the calculated statistics, a set of correlations among various physical and morphological parameters of incipient soot was proposed.
{"title":"Physical, chemical and morphological evolution of incipient soot obtained from molecular dynamics simulation of acetylene pyrolysis","authors":"Khaled Mosharraf MukutMarquette University, Milwaukee, USA, Anindya GangulyUniversity of Melbourne, Melbourne, Australia, Eirini GoudeliUniversity of Melbourne, Melbourne, Australia, Georgios A. KelesidisRutgers, The State University of New Jersey, Piscataway, USAETH Zurich, Zurich, Switzerland, Somesh P. RoyMarquette University, Milwaukee, USA","doi":"arxiv-2402.06460","DOIUrl":"https://doi.org/arxiv-2402.06460","url":null,"abstract":"Incipient soot particles obtained from a series of reactive molecular\u0000dynamics simulations were studied to understand the evolution of physical,\u0000chemical, and morphological properties of incipient soot. Reactive molecular\u0000dynamics simulations of acetylene pyrolysis were performed using ReaxFF\u0000potential at 1350, 1500, 1650, and 1800 K. A total of 3324 incipient soot\u0000particles were extracted from the simulations at various stages of development.\u0000Features such as the number of carbon and hydrogen atoms, number of ring\u0000structures, mass, C/H ratio, radius of gyration, surface area, volume, atomic\u0000fractal dimension, and density were calculated for each particle. The\u0000calculated values of density and C/H ratio matched well with experimental\u0000values reported in the literature. Based on the calculated features, the\u0000particles were classified in two types: type 1 and type 2 particles. It was\u0000found that type 1 particles show significant morphological evolution while type\u00002 particles undergo chemical restructuring without any significant\u0000morphological change. The particle volume was found to be well-correlated with\u0000the number of carbon atoms in both type 1 and type 2 particle, whereas surface\u0000area was found to be correlated with the number of carbon atoms only for type 1\u0000particles. A correlation matrix comparing the level of correlation between any\u0000two features for both type 1 and type 2 particle was created. Finally, based on\u0000the calculated statistics, a set of correlations among various physical and\u0000morphological parameters of incipient soot was proposed.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139771752","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}
Khaled Mosharraf MukutMarquette University, Milwaukee, USA, Anindya GangulyUniversity of Melbourne, Melbourne, Australia, Eirini GoudeliUniversity of Melbourne, Melbourne, Australia, Georgios A. KelesidisRutgers, The State University of New Jersey, Piscataway, USAETH Zurich, Zurich, Switzerland, Somesh P. RoyMarquette University, Milwaukee, USA
A series of reactive molecular dynamics simulations is used to study the internal structure of incipient soot particles obtained from acetylene pyrolysis. The simulations were performed using ReaxFF potential at four different temperatures. The resulting soot particles are cataloged and analyzed to obtain statistics of their mass, volume, density, C/H ratio, number of cyclic structures, and other features. A total of 3324 incipient soot particles were analyzed in this study. Based on their structural characteristics, the incipient soot particles are classified into two classes, referred to as type 1 and type 2 incipient soot particles in this work. The radial distribution of density, cyclic (5-, 6-, or 7-member rings) structures and C/H ratio inside the particles revealed a clear difference in the internal structure between type 1 and type 2 particles. These classes were further found to be well represented by the size of the particles with smaller particles in type 1 and larger particles in type 2. The radial distributions of ring structures, density, and C/H ratio indicated the presence of a dense core region in type 2 particles, whereas no clear evidence of the presence of a core was found in type 1 particles. In type 2 incipient soot particles, the boundary between the core and shell was found to be around 50%-60% of the particle radius of gyration.
{"title":"Internal structure of incipient soot from acetylene pyrolysis obtained via molecular dynamics simulations","authors":"Khaled Mosharraf MukutMarquette University, Milwaukee, USA, Anindya GangulyUniversity of Melbourne, Melbourne, Australia, Eirini GoudeliUniversity of Melbourne, Melbourne, Australia, Georgios A. KelesidisRutgers, The State University of New Jersey, Piscataway, USAETH Zurich, Zurich, Switzerland, Somesh P. RoyMarquette University, Milwaukee, USA","doi":"arxiv-2402.06456","DOIUrl":"https://doi.org/arxiv-2402.06456","url":null,"abstract":"A series of reactive molecular dynamics simulations is used to study the\u0000internal structure of incipient soot particles obtained from acetylene\u0000pyrolysis. The simulations were performed using ReaxFF potential at four\u0000different temperatures. The resulting soot particles are cataloged and analyzed\u0000to obtain statistics of their mass, volume, density, C/H ratio, number of\u0000cyclic structures, and other features. A total of 3324 incipient soot particles\u0000were analyzed in this study. Based on their structural characteristics, the\u0000incipient soot particles are classified into two classes, referred to as type 1\u0000and type 2 incipient soot particles in this work. The radial distribution of\u0000density, cyclic (5-, 6-, or 7-member rings) structures and C/H ratio inside the\u0000particles revealed a clear difference in the internal structure between type 1\u0000and type 2 particles. These classes were further found to be well represented\u0000by the size of the particles with smaller particles in type 1 and larger\u0000particles in type 2. The radial distributions of ring structures, density, and\u0000C/H ratio indicated the presence of a dense core region in type 2 particles,\u0000whereas no clear evidence of the presence of a core was found in type 1\u0000particles. In type 2 incipient soot particles, the boundary between the core\u0000and shell was found to be around 50%-60% of the particle radius of gyration.","PeriodicalId":501259,"journal":{"name":"arXiv - PHYS - Atomic and Molecular Clusters","volume":"120 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139771947","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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