Ye Cao, Hongxing Song, Xiaozhen Yan, Hao Wang, Yu F. Wang, FengChao Wu, Leilei Zhang, Qiang Wu, Huayun Geng
Uranium is considered as a very important nuclear energy material because of the huge amount of energy released. As the main products of spontaneous decay of uranium, helium is difficult to react with uranium for its chemical inertness. Therefore, bubbles will be formed inside uranium, which could greatly reduce the performance of uranium or cause the safety problems. Additionally, nuclear materials are usually operated in an environment of high-temperature and high-pressure, so it is necessary to figure out the exact state of helium inside uranium at extreme conditions. Here, we explored the strcuctural stability of U-He system under high-pressure and high-temperature by using density functional theory calculations. Two metastable phases are found between 50 and 400 GPa: U4He with space group Fmmm and U6He with space group P-1. Both are metallic and adopt layered structures. Electron localization function calculation combined with charge density difference analysis indicate that there are covalent bonds between U and U atoms in both Fmmm-U4He and P-1-U6He. Compared with the elastic modulus of α-U, the addition of helium has certain influence on the mechanical properties of uranium. Besides, first-principles molecular dynamics simulations were carried out to study the dynamical behavior of Fmmm-U4He and P-1-U6He at high-temperature. It is found that Fmmm-U4He and P-1-U6He undergo one-dimensional superionic phase transitions at 150 GPa. Our study revealed exotic structure of U-He compounds beyond the form of bubble under high-pressure and high-temperature, that might be relevant to the performance and safety issue of nuclear materials at extreme conditions.
{"title":"Theoretical Study on the Structural and Thermodynamic Properties of U-He compounds under High Pressure","authors":"Ye Cao, Hongxing Song, Xiaozhen Yan, Hao Wang, Yu F. Wang, FengChao Wu, Leilei Zhang, Qiang Wu, Huayun Geng","doi":"10.1039/d4cp02037e","DOIUrl":"https://doi.org/10.1039/d4cp02037e","url":null,"abstract":"Uranium is considered as a very important nuclear energy material because of the huge amount of energy released. As the main products of spontaneous decay of uranium, helium is difficult to react with uranium for its chemical inertness. Therefore, bubbles will be formed inside uranium, which could greatly reduce the performance of uranium or cause the safety problems. Additionally, nuclear materials are usually operated in an environment of high-temperature and high-pressure, so it is necessary to figure out the exact state of helium inside uranium at extreme conditions. Here, we explored the strcuctural stability of U-He system under high-pressure and high-temperature by using density functional theory calculations. Two metastable phases are found between 50 and 400 GPa: U4He with space group Fmmm and U6He with space group P-1. Both are metallic and adopt layered structures. Electron localization function calculation combined with charge density difference analysis indicate that there are covalent bonds between U and U atoms in both Fmmm-U4He and P-1-U6He. Compared with the elastic modulus of α-U, the addition of helium has certain influence on the mechanical properties of uranium. Besides, first-principles molecular dynamics simulations were carried out to study the dynamical behavior of Fmmm-U4He and P-1-U6He at high-temperature. It is found that Fmmm-U4He and P-1-U6He undergo one-dimensional superionic phase transitions at 150 GPa. Our study revealed exotic structure of U-He compounds beyond the form of bubble under high-pressure and high-temperature, that might be relevant to the performance and safety issue of nuclear materials at extreme conditions.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430403","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}
Iraj Maleki Shahrivar, S. Mehdi Vaez Allaei, Shahab Naghavi
Two-dimensional (2D) metal chalcogenides provide rich ground for the development of nanoscale thermoelectrics, although achieving optimal thermoelectric efficiency has yet to be a challenge. Here, we leverage the unique chemistry of tellurium (Te), renowned for its hypervalent bonding and catenation abilities, to tackle this challenge as manifested in Al2Te3 and Al2Te5 monolayers. While the former forms a straightforward covalent Al–Te network, the latter adopts a more intricate bonding mechanism, enabled by eccentric features of Te chemistry, to maintain charge balance. In Al2Te5, a square planar chain (SPC) known as polytelluride [Te3]2- is neutralized by covalently bonded [Al2Te2]2+ framework. The hypervalent nature of Te results in bizarre Born effective charges of 7 and -4 for adjacent Te atoms within the square planar chain, the feature that induces significant anharmonicity, and leads to a glass-limit of lattice thermal conductivity (κL) in Al2Te5 monolayers. Enhanced anharmonic lattice vibrations and the accordion pattern bestow glass-like, strongly anisotropic thermal conductivity to the Al2Te5 monolayer. The calculated κL values of 1.8 and 0.5 Wm-1K-1 along the a- and b-axes at 600 K are one order of magnitude lower than those of Al2Te3, and even lower than monolayers that contain heavy cations like Bi2Te3. Moreover, the tellurium chain dominates the valence band maximum and conduction band minimum of Al2Te5, leading to a high valley degeneracy of 10, and thus a high power factor and figure of merit (zT). Using rigorous first-principles calculations of electron relaxation time, the estimated hole-doped and electron-doped zT of, respectively, 1.5 and 0.5 at 600 K is achieved for Al2Te5. The pioneering zT of Al2Te5 compared to that of Al2Te3 is rooted merely in its amorphous-like lattice thermal transport and its polytelluride chain. These findings underscore the importance of aluminum telluride and polymeric-based inorganic compounds as practical and cost-effective thermoelectric materials, pending further experimental validation.
{"title":"Polytelluride square planar chain induced anharmonicity results in ultralow thermal conductivity and high thermoelectric efficiency in Al2Te5 monolayers","authors":"Iraj Maleki Shahrivar, S. Mehdi Vaez Allaei, Shahab Naghavi","doi":"10.1039/d4cp01577k","DOIUrl":"https://doi.org/10.1039/d4cp01577k","url":null,"abstract":"Two-dimensional (2D) metal chalcogenides provide rich ground for the development of nanoscale thermoelectrics, although achieving optimal thermoelectric efficiency has yet to be a challenge. Here, we leverage the unique chemistry of tellurium (Te), renowned for its hypervalent bonding and catenation abilities, to tackle this challenge as manifested in Al<small><sub>2</sub></small>Te<small><sub>3</sub></small> and Al<small><sub>2</sub></small>Te<small><sub>5</sub></small> monolayers. While the former forms a straightforward covalent Al–Te network, the latter adopts a more intricate bonding mechanism, enabled by eccentric features of Te chemistry, to maintain charge balance. In Al<small><sub>2</sub></small>Te<small><sub>5</sub></small>, a square planar chain (SPC) known as polytelluride [Te<small><sub>3</sub></small>]<small><sup>2-</sup></small> is neutralized by covalently bonded [Al<small><sub>2</sub></small>Te<small><sub>2</sub></small>]<small><sup>2+</sup></small> framework. The hypervalent nature of Te results in bizarre Born effective charges of 7 and -4 for adjacent Te atoms within the square planar chain, the feature that induces significant anharmonicity, and leads to a glass-limit of lattice thermal conductivity (κ<small><sub>L</sub></small>) in Al<small><sub>2</sub></small>Te<small><sub>5</sub></small> monolayers. Enhanced anharmonic lattice vibrations and the accordion pattern bestow glass-like, strongly anisotropic thermal conductivity to the Al<small><sub>2</sub></small>Te<small><sub>5</sub></small> monolayer. The calculated κ<small><sub>L</sub></small> values of 1.8 and 0.5 Wm<small><sup>-1</sup></small>K<small><sup>-1</sup></small> along the a- and b-axes at 600 K are one order of magnitude lower than those of Al<small><sub>2</sub></small>Te<small><sub>3</sub></small>, and even lower than monolayers that contain heavy cations like Bi<small><sub>2</sub></small>Te<small><sub>3</sub></small>. Moreover, the tellurium chain dominates the valence band maximum and conduction band minimum of Al<small><sub>2</sub></small>Te<small><sub>5</sub></small>, leading to a high valley degeneracy of 10, and thus a high power factor and figure of merit (zT). Using rigorous first-principles calculations of electron relaxation time, the estimated hole-doped and electron-doped zT of, respectively, 1.5 and 0.5 at 600 K is achieved for Al<small><sub>2</sub></small>Te<small><sub>5</sub></small>. The pioneering zT of Al<small><sub>2</sub></small>Te<small><sub>5</sub></small> compared to that of Al<small><sub>2</sub></small>Te<small><sub>3</sub></small> is rooted merely in its amorphous-like lattice thermal transport and its polytelluride chain. These findings underscore the importance of aluminum telluride and polymeric-based inorganic compounds as practical and cost-effective thermoelectric materials, pending further experimental validation.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430515","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}
Sergi Burguera, Akshay Kumar Sahu, Michael Jordan Chávez Romero, Himansu S. Biswal, Antonio Bauza
A Protein Data Bank (PDB) survey has revealed noncovalent contacts involving Mn centres and protein residues. Their geometrical features are in line with the interaction between low electron density sites located along the Mn–O/N coordination bonds (σ-holes) and the lone pairs belonging to TYR, SER or HIS residues, known as a Matere Bond (MaB). Calculations at the PBE0-D3/def2-TZVP level of theory were used to investigate the strength and shed light into the physical nature of the interaction. We expect the results presented herein will be useful for those scientists working in the fields of bioinorganic chemistry, particulary in protein-metal docking, by providing new insights into transition metal···Lewis base interactions as well as a retrospective point of view to further understand the structural and functional implications of this key transition metal ion.
蛋白质数据库（PDB）调查揭示了涉及锰中心和蛋白质残基的非共价接触。这些接触的几何特征与位于 Mn-O/N 配位键（σ孔）沿线的低电子密度位点与属于 TYR、SER 或 HIS 残基的孤对（称为马特雷键 (MaB)）之间的相互作用一致。我们利用 PBE0-D3/def2-TZVP 理论水平的计算来研究这种相互作用的强度并揭示其物理本质。我们希望本文介绍的结果能为从事生物无机化学研究，尤其是蛋白质-金属对接研究的科学家们提供新的见解，帮助他们了解过渡金属-路易斯碱的相互作用，并提供一个回顾性的视角来进一步理解这一关键过渡金属离子的结构和功能意义。
{"title":"Manganese Matere Bonds in biological systems: PDB inspection and DFT calculations","authors":"Sergi Burguera, Akshay Kumar Sahu, Michael Jordan Chávez Romero, Himansu S. Biswal, Antonio Bauza","doi":"10.1039/d4cp01701c","DOIUrl":"https://doi.org/10.1039/d4cp01701c","url":null,"abstract":"A Protein Data Bank (PDB) survey has revealed noncovalent contacts involving Mn centres and protein residues. Their geometrical features are in line with the interaction between low electron density sites located along the Mn–O/N coordination bonds (σ-holes) and the lone pairs belonging to TYR, SER or HIS residues, known as a Matere Bond (MaB). Calculations at the PBE0-D3/def2-TZVP level of theory were used to investigate the strength and shed light into the physical nature of the interaction. We expect the results presented herein will be useful for those scientists working in the fields of bioinorganic chemistry, particulary in protein-metal docking, by providing new insights into transition metal···Lewis base interactions as well as a retrospective point of view to further understand the structural and functional implications of this key transition metal ion.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436004","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}
Marta Galynska, Matheus Morato Ferreira de Moraes, Pawel Tecmer, Katharina Boguslawski
In this work, we use modern electronic structure methods to model the catalytic mechanism of different variants of the molybdenum cofactor (Moco). We investigate the dependence of various Moco model systems on structural relaxation and the importance of environmental effects for five critical points along the reaction coordinate with the DMSO and NO3− substrates. Furthermore, we scrutinize the performance of various coupled-cluster approaches for modeling the relative energies along the investigated reaction paths, focusing on several pair coupled cluster doubles (pCCD) flavors and conventional coupled cluster approximations. Moreover, we elucidate the Mo–O bond formation using orbital-based quantum information measures, which highlight the flow of σ(M−O) bond formation and σ(N/S−O) bond breaking. Our study shows that pCCD-based models are a viable alternative to conventional methods and offer us unique insights into the bonding situation along a reaction coordinate. Finally, this work highlights the importance of environmental effects or changes in the core and, consequently, in the model itself to elucidate the change in activity of different Moco variants.
{"title":"Delving into the Catalytic Mechanism of Molybdenum Cofactors: A Novel Coupled Cluster Study","authors":"Marta Galynska, Matheus Morato Ferreira de Moraes, Pawel Tecmer, Katharina Boguslawski","doi":"10.1039/d4cp01500b","DOIUrl":"https://doi.org/10.1039/d4cp01500b","url":null,"abstract":"In this work, we use modern electronic structure methods to model the catalytic mechanism of different variants of the molybdenum cofactor (Moco). We investigate the dependence of various Moco model systems on structural relaxation and the importance of environmental effects for five critical points along the reaction coordinate with the DMSO and NO3− substrates. Furthermore, we scrutinize the performance of various coupled-cluster approaches for modeling the relative energies along the investigated reaction paths, focusing on several pair coupled cluster doubles (pCCD) flavors and conventional coupled cluster approximations. Moreover, we elucidate the Mo–O bond formation using orbital-based quantum information measures, which highlight the flow of σ(M−O) bond formation and σ(N/S−O) bond breaking. Our study shows that pCCD-based models are a viable alternative to conventional methods and offer us unique insights into the bonding situation along a reaction coordinate. Finally, this work highlights the importance of environmental effects or changes in the core and, consequently, in the model itself to elucidate the change in activity of different Moco variants.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430517","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}
Ruixue Yue, Xuemin Su, Xiaodong Lv, Bingwen Zhang, Shaolong Su, Haipeng Li, Shaoqiang Guo, Jian Gong
The discovery of novel two-dimensional (2D) half-metallic materials with robust ferromagnetic (FM) order and high Curie temperature (Tc) is attractive for the advancement of next-generation spintronic devices. Here, we proposed a stable 2D intrinsic FM half-metallicity, i.e., CrSc2Te4 monolayer, which was constructed by intercalating a monolayer of 1T-CrTe2-type sandwiched between two layers of 2H-ScTe2 monolayers. Our calculations reveal that it exhibits exceptional dynamical, thermal, and mechanical stability accompanied by a robust half-metallicity characterized by a wide bandgap of 1.02 eV and FM ordering with a high Tc of 326 K. Notably, these properties remain intact in almost the entire range of biaxial strain from -5% to 5%. Furthermore, our investigations demonstrate excellent spin transport capabilities, including an outstanding spin-filtering effect, and a remarkably high tunneling magnetoresistance ratio peaking at 6087.07%. The remarkable magnetic features of 2D CrSc2Te4 monolayer with root temperature FM, intrinsic half-metallicity, and 100% spin-polarization render it a promising candidate for the next-generation high-performance spintronic nanodevices as well as high-density magnetic recording and sensors.
{"title":"Room-temperature Ferromagnetism, Half-metallicity and Spin Transport in Monolayer CrSc2Te4-Based Magnetic Tunnel Junction Devices","authors":"Ruixue Yue, Xuemin Su, Xiaodong Lv, Bingwen Zhang, Shaolong Su, Haipeng Li, Shaoqiang Guo, Jian Gong","doi":"10.1039/d4cp01660b","DOIUrl":"https://doi.org/10.1039/d4cp01660b","url":null,"abstract":"The discovery of novel two-dimensional (2D) half-metallic materials with robust ferromagnetic (FM) order and high Curie temperature (Tc) is attractive for the advancement of next-generation spintronic devices. Here, we proposed a stable 2D intrinsic FM half-metallicity, i.e., CrSc2Te4 monolayer, which was constructed by intercalating a monolayer of 1T-CrTe2-type sandwiched between two layers of 2H-ScTe2 monolayers. Our calculations reveal that it exhibits exceptional dynamical, thermal, and mechanical stability accompanied by a robust half-metallicity characterized by a wide bandgap of 1.02 eV and FM ordering with a high Tc of 326 K. Notably, these properties remain intact in almost the entire range of biaxial strain from -5% to 5%. Furthermore, our investigations demonstrate excellent spin transport capabilities, including an outstanding spin-filtering effect, and a remarkably high tunneling magnetoresistance ratio peaking at 6087.07%. The remarkable magnetic features of 2D CrSc2Te4 monolayer with root temperature FM, intrinsic half-metallicity, and 100% spin-polarization render it a promising candidate for the next-generation high-performance spintronic nanodevices as well as high-density magnetic recording and sensors.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430341","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}
Diksha Garg, Pragya Chopra, Jason W.L. Lee, Denis Tikhonov, Sonu Kumar, Oender Akcaalan, Felix Allum, Rebecca Boll, Alexander A. Butler, Benjamin Erk, Eva Gougoula, Sébastien Gruet, Lanhai He, David Heathcote, Ellen Jones, Mehdi Kazemi, Jan Lahl, Alexander K. Lemmens, Zhihao Liu, Donatella Loru, Sylvain Maclot, Robert Mason, James Merrick, Erland Müller, Terry Mullins, Christina C. Papadopoulou, Christopher Passow, Jasper Peschel, Marius Plach, Daniel Ramm, Patrick Andrew Robertson, Dimitrios Rompotis, Alcides Simao, Amanda L Steber, Ayhan Tajalli, Atia Tul-Noor, Nidin Vadassery, Ivo S. Vinklarek, Simone Techert, Jochen Küpper, Anouk Rijs, Daniel Rolles, Mark Brouard, Sadia Bari, Per Eng-Johnsson, Claire Vallance, Michael Burt, Bastian Manschwetus, Melanie Schnell
We present an investigation of the ultrafast dynamics of the polycyclic aromatic hydrocarbon fluorene initiated by an intense femtosecond near-infrared laser pulse (810~nm) and probed by a weak visible pulse (405~nm). Using a multichannel detection scheme (mass spectra, electron and ion velocity-map imaging), we provide a full disentanglement of the complex dynamics of the vibronically excited parent molecule, its excited ionic states, and fragments. We observed various channels resulting from the strong-field ionization regime. In particular, we observed the formation of the unstable tetracation of fluorene, above-threshold ionization features in the photoelectron spectra, and evidence of ubiquitous secondary fragmentation. We produced a global fit of all observed time-dependent photoelectron and photoion channels. This global fit includes four parent ions extracted from the mass spectra, 15 kinetic-energy-resolved ionic fragments extracted from ion velocity map imaging, and five photoelectron channels obtained from electron velocity map imaging. The fit allowed for the extraction of 60 lifetimes of various metastable photoinduced intermediates.
{"title":"Ultrafast dynamics of fluorene initiated by highly intense laser fields","authors":"Diksha Garg, Pragya Chopra, Jason W.L. Lee, Denis Tikhonov, Sonu Kumar, Oender Akcaalan, Felix Allum, Rebecca Boll, Alexander A. Butler, Benjamin Erk, Eva Gougoula, Sébastien Gruet, Lanhai He, David Heathcote, Ellen Jones, Mehdi Kazemi, Jan Lahl, Alexander K. Lemmens, Zhihao Liu, Donatella Loru, Sylvain Maclot, Robert Mason, James Merrick, Erland Müller, Terry Mullins, Christina C. Papadopoulou, Christopher Passow, Jasper Peschel, Marius Plach, Daniel Ramm, Patrick Andrew Robertson, Dimitrios Rompotis, Alcides Simao, Amanda L Steber, Ayhan Tajalli, Atia Tul-Noor, Nidin Vadassery, Ivo S. Vinklarek, Simone Techert, Jochen Küpper, Anouk Rijs, Daniel Rolles, Mark Brouard, Sadia Bari, Per Eng-Johnsson, Claire Vallance, Michael Burt, Bastian Manschwetus, Melanie Schnell","doi":"10.1039/d3cp05063g","DOIUrl":"https://doi.org/10.1039/d3cp05063g","url":null,"abstract":"We present an investigation of the ultrafast dynamics of the polycyclic aromatic hydrocarbon fluorene initiated by an intense femtosecond near-infrared laser pulse (810~nm) and probed by a weak visible pulse (405~nm). Using a multichannel detection scheme (mass spectra, electron and ion velocity-map imaging), we provide a full disentanglement of the complex dynamics of the vibronically excited parent molecule, its excited ionic states, and fragments. We observed various channels resulting from the strong-field ionization regime. In particular, we observed the formation of the unstable tetracation of fluorene, above-threshold ionization features in the photoelectron spectra, and evidence of ubiquitous secondary fragmentation. We produced a global fit of all observed time-dependent photoelectron and photoion channels. This global fit includes four parent ions extracted from the mass spectra, 15 kinetic-energy-resolved ionic fragments extracted from ion velocity map imaging, and five photoelectron channels obtained from electron velocity map imaging. The fit allowed for the extraction of 60 lifetimes of various metastable photoinduced intermediates.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430518","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}
The ground state and excited state resonance dipole–dipole interaction energy between two elongated conducting molecules is explored in this study. We review the current status for ground state interactions. This interaction is found to be of a much longer range than in the case when the molecules are pointlike and nonconducting. These are well known results found earlier by Davies, Ninham, and Richmond, and later, using a different formalism, by Rubio and co-workers. We show how the theory can be extended to excited state interactions. A characteristic property observed from our calculation is that the interaction energy dependence on separation (R) follows f(R)/R2 for both resonance and van der Waals cases in the long-range limit. Under some limits, f(R) has a logarithmic dependency, while under others, it has constant values. We predict an unusual slow decay rate for the energy transfer between conducting molecules.
{"title":"Dispersion interaction between thin conducting cylinders","authors":"Subhojit Pal, Iver Brevik and Mathias Boström","doi":"10.1039/D4CP01664E","DOIUrl":"10.1039/D4CP01664E","url":null,"abstract":"<p >The ground state and excited state resonance dipole–dipole interaction energy between two elongated conducting molecules is explored in this study. We review the current status for ground state interactions. This interaction is found to be of a much longer range than in the case when the molecules are pointlike and nonconducting. These are well known results found earlier by Davies, Ninham, and Richmond, and later, using a different formalism, by Rubio and co-workers. We show how the theory can be extended to excited state interactions. A characteristic property observed from our calculation is that the interaction energy dependence on separation (<em>R</em>) follows <em>f</em>(<em>R</em>)/<em>R</em><small><sup>2</sup></small> for both resonance and van der Waals cases in the long-range limit. Under some limits, <em>f</em>(<em>R</em>) has a logarithmic dependency, while under others, it has constant values. We predict an unusual slow decay rate for the energy transfer between conducting molecules.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141416735","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}
Monitor of reactive oxygen species (ROS), such as O2•, etc. in organisms is of great significance, not only for their essential role in biological processes, but their excessive production may also result in many diseases. Flavin (FL) is a fluorophore naturally exists in flavoenzymes, and its fluorescent emission (FE) would become negligible when reduced. This enables the application of FL derivatives as fluorescent sensors for ROS. We presented a theoretical investigation to address the impact of amino substitution on the photophysical properties of amino flavins (AmFLs). Resulting from the interplay of electronic and positional effects, amination at C8 enhances the electronic coupling between ground state and first singlet excited state by enlarging the adiabatic energy change of electronic transitions and emission transition dipole moments, weakens the vibronic coupling by decrease the contribution of isoalloxazine to frontier molecular orbitals, redshifts the absorption band, and enhances fluorescent emission drastically in 8AmFL. The theoretically estimated fluorescent emission intensity of 8AmFL is ~40 times that of FL, rendering its potential application as fluorescent sensor.
{"title":"Lightening Flavin by Amination for Fluorescent Sensing","authors":"Huimin Guo, Siyu Liu, Xin Liu, Lijun Zhang","doi":"10.1039/d4cp01525h","DOIUrl":"https://doi.org/10.1039/d4cp01525h","url":null,"abstract":"Monitor of reactive oxygen species (ROS), such as O2•, etc. in organisms is of great significance, not only for their essential role in biological processes, but their excessive production may also result in many diseases. Flavin (FL) is a fluorophore naturally exists in flavoenzymes, and its fluorescent emission (FE) would become negligible when reduced. This enables the application of FL derivatives as fluorescent sensors for ROS. We presented a theoretical investigation to address the impact of amino substitution on the photophysical properties of amino flavins (AmFLs). Resulting from the interplay of electronic and positional effects, amination at C8 enhances the electronic coupling between ground state and first singlet excited state by enlarging the adiabatic energy change of electronic transitions and emission transition dipole moments, weakens the vibronic coupling by decrease the contribution of isoalloxazine to frontier molecular orbitals, redshifts the absorption band, and enhances fluorescent emission drastically in 8AmFL. The theoretically estimated fluorescent emission intensity of 8AmFL is ~40 times that of FL, rendering its potential application as fluorescent sensor.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425464","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}
Haichen Wang, Tomas Rauch, Andres Tellez, Wirtz Ludger, Aldo Humberto Romero Castro, Miguel A., L. Marques
We present a computational study of the M3QX7 family of two-dimensional compounds, focusing specifically on their flat-band properties. We use a high-throughput search methodology, accelerated by machine learning, to explore the vast chemical space spawned by this family. In this way, we identify numerous stable 2D compounds within the M3QX7 family. We investigate how the chemical composition can be manipulated to modulate the position and dispersion of the flat bands. By employing a tight-binding model we explain the formation of flat bands as a result of a relatively loose connection between triangular M3QX3 clusters via bridges of X atoms. The model provides an understanding of the residual interactions that can impact the band dispersion. The same loose connection between clusters that leads to strongly localized electronic states and thus flat electronic bands also leads to localized phonon modes and flat bands in the phonon dispersion.
我们介绍了对二维化合物 M3QX7 家族的计算研究，特别关注它们的平带特性。我们利用机器学习加速的高通量搜索方法来探索该家族产生的巨大化学空间。通过这种方法，我们在 M3QX7 家族中发现了许多稳定的二维化合物。我们研究了如何操纵化学成分来调节平带的位置和分散。通过采用紧密结合模型，我们解释了平带的形成是三角形 M3QX3 团簇之间通过 X 原子桥形成相对松散连接的结果。该模型提供了对可能影响带色散的残余相互作用的理解。簇之间的松散连接会导致强局部电子态，从而产生平坦的电子带，同样也会导致局部声子模式和声子频散中的平坦带。
{"title":"Exploring Flat-Band Properties in Two-Dimensional M3QX7 Compounds","authors":"Haichen Wang, Tomas Rauch, Andres Tellez, Wirtz Ludger, Aldo Humberto Romero Castro, Miguel A., L. Marques","doi":"10.1039/d4cp01196a","DOIUrl":"https://doi.org/10.1039/d4cp01196a","url":null,"abstract":"We present a computational study of the M<small><sub>3</sub></small>QX<small><sub>7</sub></small> family of two-dimensional compounds, focusing specifically on their flat-band properties. We use a high-throughput search methodology, accelerated by machine learning, to explore the vast chemical space spawned by this family. In this way, we identify numerous stable 2D compounds within the M<small><sub>3</sub></small>QX<small><sub>7</sub></small> family. We investigate how the chemical composition can be manipulated to modulate the position and dispersion of the flat bands. By employing a tight-binding model we explain the formation of flat bands as a result of a relatively loose connection between triangular M<small><sub>3</sub></small>QX<small><sub>3</sub></small> clusters via bridges of X atoms. The model provides an understanding of the residual interactions that can impact the band dispersion. The same loose connection between clusters that leads to strongly localized electronic states and thus flat electronic bands also leads to localized phonon modes and flat bands in the phonon dispersion.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430514","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}
In our recent work, we successfully developed an innovative method based on pin-water discharge for preparing ultralong-lasting plasma-activated water (PAW) with a lifetime of up to 720 hours at room temperature. However, the impact of power polarity on the preparation method for ultralong-lasting PAW remains unclear. In this study, we discovered that ultralong-lasting PAW could only be achieved with positive polarity. Further analysis of the liquid reactive oxygen and nitrogen species (RONS) revealed that the absence of H2O2 in the discharge chamber was crucial for the failure of ultralong-lasting PAW preparation at negative polarity. To elucidate the mechanism underlying the generation of RONS at different polarities, we conducted plasma feature diagnosis, compared discharge morphologies, and performed theoretical analyses based on chemical reactions. Our results indicated that the introduction of water vapor molecules through intense spraying at positive polarity led to an increase in the generation of H2O2-related source particles, while also interfering with N2-related electron collision reactions and chemical reaction coefficients, ultimately affecting the production of NO2−. Consequently, there was relatively less liquid NO2− and more abundant H2O2 in the discharge chamber at positive polarity, whereas the opposite trend was observed for these two key RONS at negative polarity. Furthermore, the minimal amount of NO2− at positive polarity and the tiny amount of H2O2 at negative polarity in the discharge chamber would be respectively consumed by the relatively abundant H2O2 at positive polarity and NO2− at negative polarity.
{"title":"Insights into the mechanisms of plasma physicochemical characteristics on ultralong-lasting plasma-activated water: the influence of DC power polarity on RONS generation†","authors":"Congfu Ran, Xiongfeng Zhou and Kun Liu","doi":"10.1039/D4CP00384E","DOIUrl":"10.1039/D4CP00384E","url":null,"abstract":"<p >In our recent work, we successfully developed an innovative method based on pin-water discharge for preparing ultralong-lasting plasma-activated water (PAW) with a lifetime of up to 720 hours at room temperature. However, the impact of power polarity on the preparation method for ultralong-lasting PAW remains unclear. In this study, we discovered that ultralong-lasting PAW could only be achieved with positive polarity. Further analysis of the liquid reactive oxygen and nitrogen species (RONS) revealed that the absence of H<small><sub>2</sub></small>O<small><sub>2</sub></small> in the discharge chamber was crucial for the failure of ultralong-lasting PAW preparation at negative polarity. To elucidate the mechanism underlying the generation of RONS at different polarities, we conducted plasma feature diagnosis, compared discharge morphologies, and performed theoretical analyses based on chemical reactions. Our results indicated that the introduction of water vapor molecules through intense spraying at positive polarity led to an increase in the generation of H<small><sub>2</sub></small>O<small><sub>2</sub></small>-related source particles, while also interfering with N<small><sub>2</sub></small>-related electron collision reactions and chemical reaction coefficients, ultimately affecting the production of NO<small><sub>2</sub></small><small><sup>−</sup></small>. Consequently, there was relatively less liquid NO<small><sub>2</sub></small><small><sup>−</sup></small> and more abundant H<small><sub>2</sub></small>O<small><sub>2</sub></small> in the discharge chamber at positive polarity, whereas the opposite trend was observed for these two key RONS at negative polarity. Furthermore, the minimal amount of NO<small><sub>2</sub></small><small><sup>−</sup></small> at positive polarity and the tiny amount of H<small><sub>2</sub></small>O<small><sub>2</sub></small> at negative polarity in the discharge chamber would be respectively consumed by the relatively abundant H<small><sub>2</sub></small>O<small><sub>2</sub></small> at positive polarity and NO<small><sub>2</sub></small><small><sup>−</sup></small> at negative polarity.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425397","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：