Chi Deng, Hui Zhang, Yang Du, Xia Du, Yan Shang, Hongda Yang, Xuan Wang, Qingguo Chen, Zesheng Li
Cross-linked polyethylene (XLPE) insulation has been used in most advanced power cable technology. Strategies for decreasing the amount of antioxidants have been proposed to reduce conductivity further. In this study, the structural design of a new dual-functional antioxidant has been established. Theoretical investigation of the antioxidative behavior and grafting reaction of the new antioxidant by ultraviolet (UV) radiation was performed using the density functional theory (DFT) method. The reaction potential energy information of the six reaction channels at the B3LYP/6-311+G (d,p) level was obtained. Frontier molecular orbitals (MOs) and natural bond orbital (NBO) charge populations of the designed antioxidant molecule were analyzed. The calculation results indicate that the reaction Gibbs energy barrier of the designed antioxidant and O2 required to achieve the antioxidative effect is about 0.8 eV lower than that of the polyethylene chain. Moreover, due to the lower reaction Gibbs energy barrier, the reaction active site of the designed antioxidant accepting H is located on the O of the CO groups. The proposed mechanism would be beneficial to understanding the molecular functions of antioxidants and further broadening the design ideas of thermoplastic insulation materials for future advanced power cables.
交联聚乙烯(XLPE)绝缘层已被用于最先进的电力电缆技术中。有人提出了减少抗氧化剂用量的策略,以进一步降低导电性。本研究建立了一种新型双功能抗氧化剂的结构设计。采用密度泛函理论(DFT)方法对新型抗氧化剂在紫外线(UV)辐射下的抗氧化行为和接枝反应进行了理论研究。在 B3LYP/6-311+G (d,p) 水平上获得了六个反应通道的反应势能信息。分析了设计的抗氧化剂分子的前沿分子轨道(MOs)和天然键轨道(NBO)电荷群。计算结果表明,设计的抗氧化剂与 O2 实现抗氧化效果所需的反应吉布斯能障比聚乙烯链低约 0.8 eV。此外,由于反应吉布斯能垒较低,设计的抗氧化剂接受 H 的反应活性位点位于 CO 基团的 O 上。所提出的机理将有助于理解抗氧化剂的分子功能,并进一步拓宽未来先进电力电缆热塑性绝缘材料的设计思路。
{"title":"Theoretical Study of the Grafting Reaction of a New Antioxidant to Cross-Linked Polyethylene and the Antioxidation Mechanism","authors":"Chi Deng, Hui Zhang, Yang Du, Xia Du, Yan Shang, Hongda Yang, Xuan Wang, Qingguo Chen, Zesheng Li","doi":"10.1002/qua.27492","DOIUrl":"https://doi.org/10.1002/qua.27492","url":null,"abstract":"<div>\u0000 \u0000 <p>Cross-linked polyethylene (XLPE) insulation has been used in most advanced power cable technology. Strategies for decreasing the amount of antioxidants have been proposed to reduce conductivity further. In this study, the structural design of a new dual-functional antioxidant has been established. Theoretical investigation of the antioxidative behavior and grafting reaction of the new antioxidant by ultraviolet (UV) radiation was performed using the density functional theory (DFT) method. The reaction potential energy information of the six reaction channels at the B3LYP/6-311+G (<i>d,p</i>) level was obtained. Frontier molecular orbitals (MOs) and natural bond orbital (NBO) charge populations of the designed antioxidant molecule were analyzed. The calculation results indicate that the reaction Gibbs energy barrier of the designed antioxidant and O<sub>2</sub> required to achieve the antioxidative effect is about 0.8 eV lower than that of the polyethylene chain. Moreover, due to the lower reaction Gibbs energy barrier, the reaction active site of the designed antioxidant accepting H is located on the O of the CO groups. The proposed mechanism would be beneficial to understanding the molecular functions of antioxidants and further broadening the design ideas of thermoplastic insulation materials for future advanced power cables.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429018","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 double-stranded DNA, a rapid deprotonation of guanine radical cation (G•+) hinders the long-distance transfer of positive charge (hole). It is significant to explore the proton transfer of G•+ for designing other DNA structures with high electrical conductivity. The deprotonation of G•+ is explored in the 1H2O, 2H2O, 3H2O, and 9H2O models by quantum mechanics (QM) method. The results indicate that the second hydration shell facilitates proton transfer. The QM/molecular mechanics (MM) (ABEEM) method accurately simulates polarization and charge transfer effects through the implementation of the reactive valence-state electronegativity piecewise functions and setting local charge conservation conditions. The QM/MM(ABEEM) method has been developed to investigate the 9H2O model. The obtained activation energy (16.3 ± 0.8 kJ/mol) through molecular dynamics simulations is consistent with experimental data (15.1 ± 1.5 kJ/mol), demonstrating the accuracy of the QM/MM(ABEEM) method in simulating proton transfer in the DNA system. The deprotonation rate of G•+ in the free base (1.5 × 107 s−1) is faster than that of G•+ within double-stranded DNA (106–107 s−1), which indicates that the free G base is an avoidable participant when designing hole transfer carrier due to its rapid deprotonation rate. Concurrently, the relationship between the proton transfer distance and potential barrier is monotone increasing, meaning that the long-range proton transfer corresponds to high energy barrier. The molecule involved in long-range proton transfer of G•+ is more suitable as DNA electronic devices. This research provides valuable microscopic insight into deprotonation to advance the advancement of DNA structures with high electrical conductivity.
在双链 DNA 中,鸟嘌呤基阳离子(G-+)的快速去质子化阻碍了正电荷(空穴)的长距离转移。探索 G-+ 的质子转移对于设计其他具有高导电性的 DNA 结构意义重大。本文采用量子力学(QM)方法探讨了 G-+ 在 1H2O、2H2O、3H2O 和 9H2O 模型中的去质子化过程。结果表明,第二水合壳促进了质子的转移。量子力学/分子力学(MM)(ABEEM)方法通过实施反应价态电负性片断函数和设置局部电荷守恒条件,精确模拟了极化和电荷转移效应。我们开发了 QM/MM(ABEEM)方法来研究 9H2O 模型。分子动力学模拟得到的活化能(16.3 ± 0.8 kJ/mol)与实验数据(15.1 ± 1.5 kJ/mol)一致,证明了 QM/MM(ABEEM)方法在模拟 DNA 系统质子转移方面的准确性。游离碱基中 G-+ 的去质子化速率(1.5 × 107 s-1)快于双链 DNA 中 G-+ 的去质子化速率(106-107 s-1),这表明游离 G 碱基由于其快速的去质子化速率,在设计空穴传输载体时是可以避免的参与者。同时,质子转移距离与势垒之间的关系是单调递增的,这意味着长程质子转移对应着高能量势垒。参与 G-+ 长程质子转移的分子更适合作为 DNA 电子器件。这项研究为了解去质子化提供了宝贵的微观视角,有助于推动具有高导电性的 DNA 结构的发展。
{"title":"Insights Into Guanine Radical Cation Deprotonation Using the Quantum Mechanics and Quantum Mechanics/Molecular Mechanics (ABEEM) Methods","authors":"Yue Wang, Cui Liu, Lidong Gong, Zhongzhi Yang","doi":"10.1002/qua.27491","DOIUrl":"https://doi.org/10.1002/qua.27491","url":null,"abstract":"<div>\u0000 \u0000 <p>In double-stranded DNA, a rapid deprotonation of guanine radical cation (G<sup>•+</sup>) hinders the long-distance transfer of positive charge (hole). It is significant to explore the proton transfer of G<sup>•+</sup> for designing other DNA structures with high electrical conductivity. The deprotonation of G<sup>•+</sup> is explored in the 1H<sub>2</sub>O, 2H<sub>2</sub>O, 3H<sub>2</sub>O, and 9H<sub>2</sub>O models by quantum mechanics (QM) method. The results indicate that the second hydration shell facilitates proton transfer. The QM/molecular mechanics (MM) (ABEEM) method accurately simulates polarization and charge transfer effects through the implementation of the reactive valence-state electronegativity piecewise functions and setting local charge conservation conditions. The QM/MM(ABEEM) method has been developed to investigate the 9H<sub>2</sub>O model. The obtained activation energy (16.3 ± 0.8 kJ/mol) through molecular dynamics simulations is consistent with experimental data (15.1 ± 1.5 kJ/mol), demonstrating the accuracy of the QM/MM(ABEEM) method in simulating proton transfer in the DNA system. The deprotonation rate of G<sup>•+</sup> in the free base (1.5 × 10<sup>7</sup> s<sup>−1</sup>) is faster than that of G<sup>•+</sup> within double-stranded DNA (10<sup>6</sup>–10<sup>7</sup> s<sup>−1</sup>), which indicates that the free G base is an avoidable participant when designing hole transfer carrier due to its rapid deprotonation rate. Concurrently, the relationship between the proton transfer distance and potential barrier is monotone increasing, meaning that the long-range proton transfer corresponds to high energy barrier. The molecule involved in long-range proton transfer of G<sup>•+</sup> is more suitable as DNA electronic devices. This research provides valuable microscopic insight into deprotonation to advance the advancement of DNA structures with high electrical conductivity.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359928","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}
Imidazole structures are significant molecular frameworks in pharmaceutical and energetic material research. The synthesis efficiency and yield of their derivatives often vary greatly, making it challenging to establish reaction regularity. In this study, we investigated two types of imidazole derivatives with notably different synthesis efficiencies and yields. Our findings reveal that the catalysis of H2O molecules is crucial for ensuring synthesis efficiency, while side reactions are influenced by the acidity of the solution during the process, thereby affecting the synthesis yield. We observed that the energy barrier for the H2O-catalyzed ipsilateral H transfer process was reduced to 12.0 from 40.1 kcal/mol, significantly enhancing the reaction efficiency. The synthesis of 34-dihydroxyimidazolidine-2-ketone was found to have a low yield of 19.2% due to competitive side reactions in the reaction system, which have higher energy barriers compared to the desired synthesis pathway. These findings provide a theoretical foundation for future research to optimize the synthesis of imidazole derivatives. Enhancing synthesis conditions could significantly benefit pharmaceutical applications and the development of advanced energetic materials.
{"title":"Theoretical Study on the Synthesis Efficiency and Yield of Imidazole Derivatives Based on the Glyoxal and Diamine","authors":"Huaxin Liu, Zhiyang Chen, Yinhua Ma, Meiheng Lv, Shuhui Yin, Fangjian Shang, Jianyong Liu","doi":"10.1002/qua.27476","DOIUrl":"https://doi.org/10.1002/qua.27476","url":null,"abstract":"<div>\u0000 \u0000 <p>Imidazole structures are significant molecular frameworks in pharmaceutical and energetic material research. The synthesis efficiency and yield of their derivatives often vary greatly, making it challenging to establish reaction regularity. In this study, we investigated two types of imidazole derivatives with notably different synthesis efficiencies and yields. Our findings reveal that the catalysis of H<sub>2</sub>O molecules is crucial for ensuring synthesis efficiency, while side reactions are influenced by the acidity of the solution during the process, thereby affecting the synthesis yield. We observed that the energy barrier for the H<sub>2</sub>O-catalyzed ipsilateral H transfer process was reduced to 12.0 from 40.1 kcal/mol, significantly enhancing the reaction efficiency. The synthesis of 34-dihydroxyimidazolidine-2-ketone was found to have a low yield of 19.2% due to competitive side reactions in the reaction system, which have higher energy barriers compared to the desired synthesis pathway. These findings provide a theoretical foundation for future research to optimize the synthesis of imidazole derivatives. Enhancing synthesis conditions could significantly benefit pharmaceutical applications and the development of advanced energetic materials.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324702","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}
This work is devoted to the study of the influence of protonation on the photophysical properties of dimethylamino-substituted styryl dyes. The formation of a bond on the unshared nitrogen electron pair involved in conjugation with the dye chromophore changes the mobility of the terminal group of the donor fragment and thereby “switches” the molecule from n-π* to π-π* mode. The correlations found between changes in the electron density of the dye in native form and during protonation and changes in its properties contribute to the study of the ground and excited states of these compounds and the energy transitions between them. Comparison with analog compounds and consideration of vibronic effects allow us to evaluate the potential advantages and limitations of the TD-DFT method in the calculation of electronic transitions in styryl dyes. The work contributes to the understanding of the influence of protonation on the behavior of dyes with a nitrogen atom in the donor part of the chromophore of the molecule. The patterns found can be applied to similar chromophore systems.
{"title":"Computational Approach to the Study of Acidochromic Properties of Donor-π-Acceptor Systems Based on Dimethylamino-Substituted Dyes With Intramolecular Charge Transfer","authors":"Evgeny Mediantsev, Nikita Dubinets, Natalia Lobova","doi":"10.1002/qua.27488","DOIUrl":"https://doi.org/10.1002/qua.27488","url":null,"abstract":"<div>\u0000 \u0000 <p>This work is devoted to the study of the influence of protonation on the photophysical properties of dimethylamino-substituted styryl dyes. The formation of a bond on the unshared nitrogen electron pair involved in conjugation with the dye chromophore changes the mobility of the terminal group of the donor fragment and thereby “switches” the molecule from n-π* to π-π* mode. The correlations found between changes in the electron density of the dye in native form and during protonation and changes in its properties contribute to the study of the ground and excited states of these compounds and the energy transitions between them. Comparison with analog compounds and consideration of vibronic effects allow us to evaluate the potential advantages and limitations of the TD-DFT method in the calculation of electronic transitions in styryl dyes. The work contributes to the understanding of the influence of protonation on the behavior of dyes with a nitrogen atom in the donor part of the chromophore of the molecule. The patterns found can be applied to similar chromophore systems.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324704","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}
Minnet Can Kandemir, Bilge Bicak, Serda Kecel-Gunduz, Gizem Akman
Present investigation deals with the structural and pharmacokinetic properties of hydantoin-based drug molecules such as phenytoin, mephenytoin, and ethotoin. Hydantoin-based drugs are widely used as anticonvulsants in the treatment of epilepsy. In this study, optimized structures, and theoretical vibrational wavenumbers of phenytoin, mephenytoin, and ethotoin molecules were determined using Gaussian 09 program with density functional theory (DFT) and B3LYP/6-311++G(d,p) basis set, vibration mode assignments were performed with the GAR2PED program, and the theoretical results were supported by FTIR and Raman spectroscopy. In addition, thermodynamic parameters, Mulliken charge values, HOMO-LUMO, natural bond orbital, MEP, hyperpolarizability analyzes of hydantoin-based molecules were performed. Docking analysis of all molecules with the GABA-AT receptor, which has an important place in epilepsy studies, were also carried out. Then, the molecular dynamic (MD) simulations of the hydantoin-based drugs-GABA-AT complexes were realized for 50 ns. ADMET profiles of all molecules were determined and presented by parameters of toxicity and drug-likeness. Additionally, to determine the effects of hydantoin-based drugs on glioblastoma cells, cytotoxic effects of phenytoin, mephenytoin, and ethotoin were evaluated on U-87 Human glioblastoma cell line.
{"title":"Investigation of Hydantoin-Based Drugs Used in the Treatment of Epilepsy Using Quantum Chemical Calculations, Molecular Docking, Molecular Dynamics, ADMET, In Vitro, and Spectroscopic Methods","authors":"Minnet Can Kandemir, Bilge Bicak, Serda Kecel-Gunduz, Gizem Akman","doi":"10.1002/qua.27485","DOIUrl":"https://doi.org/10.1002/qua.27485","url":null,"abstract":"<p>Present investigation deals with the structural and pharmacokinetic properties of hydantoin-based drug molecules such as phenytoin, mephenytoin, and ethotoin. Hydantoin-based drugs are widely used as anticonvulsants in the treatment of epilepsy. In this study, optimized structures, and theoretical vibrational wavenumbers of phenytoin, mephenytoin, and ethotoin molecules were determined using Gaussian 09 program with density functional theory (DFT) and B3LYP/6-311++G(d,p) basis set, vibration mode assignments were performed with the GAR2PED program, and the theoretical results were supported by FTIR and Raman spectroscopy. In addition, thermodynamic parameters, Mulliken charge values, HOMO-LUMO, natural bond orbital, MEP, hyperpolarizability analyzes of hydantoin-based molecules were performed. Docking analysis of all molecules with the GABA-AT receptor, which has an important place in epilepsy studies, were also carried out. Then, the molecular dynamic (MD) simulations of the hydantoin-based drugs-GABA-AT complexes were realized for 50 ns. ADMET profiles of all molecules were determined and presented by parameters of toxicity and drug-likeness. Additionally, to determine the effects of hydantoin-based drugs on glioblastoma cells, cytotoxic effects of phenytoin, mephenytoin, and ethotoin were evaluated on U-87 Human glioblastoma cell line.</p>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qua.27485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pacharaporn Krawmanee, M. Paul Gleeson, Duangkamol Gleeson
Synthesis of novel benzothiazoles via intramolecular CS bond formation reactions is increasingly being explored since they have been found in a wide range of natural products and pharmaceutical agents. Sharma et al. reported the ruthenium-catalyzed preparation of novel benzothiazole derivatives from N-arylthiourea precursors, with a range of reaction yields and selectivity being observed. We have employed a density functional theory-based computational model to investigate the reaction mechanism leading to the benzothiazole product and help uncover the origin of the differing experimental yields and substrate specificities. We proposed a modified mechanistic scheme where the rate-determining step to be the synchronized breaking of the peroxide bond of the oxidizing agent with the concomitant proton-coupled electron transfer from the haloarene urea and a Ru-bound water molecule, not electrophilic RuC bond activation. Evidence for this being the rate-determining step is (a) the barrier is consistent with a lack of kinetic isotope effects associated with the ortho-H atom and (b) the computed rate-determining barriers for 10 N-arylthiourea substrates show good correlation with the observed yield.
{"title":"Computational Investigation of the Ru-Mediated Preparation of Benzothiazoles From N-Arylthioureas: Elucidation of the Reaction Mechanism and the Origin of Differing Substrate Reactivity","authors":"Pacharaporn Krawmanee, M. Paul Gleeson, Duangkamol Gleeson","doi":"10.1002/qua.27480","DOIUrl":"https://doi.org/10.1002/qua.27480","url":null,"abstract":"<div>\u0000 \u0000 <p>Synthesis of novel benzothiazoles via intramolecular C<span></span>S bond formation reactions is increasingly being explored since they have been found in a wide range of natural products and pharmaceutical agents. Sharma et al. reported the ruthenium-catalyzed preparation of novel benzothiazole derivatives from <i>N</i>-arylthiourea precursors, with a range of reaction yields and selectivity being observed. We have employed a density functional theory-based computational model to investigate the reaction mechanism leading to the benzothiazole product and help uncover the origin of the differing experimental yields and substrate specificities. We proposed a modified mechanistic scheme where the rate-determining step to be the synchronized breaking of the peroxide bond of the oxidizing agent with the concomitant proton-coupled electron transfer from the haloarene urea and a Ru-bound water molecule, not electrophilic Ru<span></span>C bond activation. Evidence for this being the rate-determining step is (a) the barrier is consistent with a lack of kinetic isotope effects associated with the <i>ortho</i>-H atom and (b) the computed rate-determining barriers for 10 <i>N</i>-arylthiourea substrates show good correlation with the observed yield.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316893","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}
Aparna Dixit, Arti Saxena, Jisha Annie Abraham, Shubha Dubey, Ramesh Sharma, Saif M. H. Qaid, Ivan Štich, Muhammad Aslam, Anatoly Zetsepin
Utilizing DFT along with Boltzmann transport theory, the structural, elastic, electrical, optical, and thermoelectric properties of half-Heusler compound RhTiP have been calculated in principle to examine the pressure effect in the range of 0–40 GPa. As pressure increases, the volume and normalized lattice parameter decreased. In addition to satisfying the Born stability criterion, which ensured the compound RhTiP “natural stability,” the zero pressure elastic constants and the pressure-dependent elastic constants are positive up to 40 GPa. The band structure computations guarantee the semiconductor nature of RhTiP, as demonstrated by the presence of electronic band gap of 1.035 eV at zero pressure. Using the Voigt-Reuss-Hill (VRH) averaging scheme under pressure, we have determined the values of this compound's bulk modulus , shear modulus , Young's modulus , Pugh ratio , Poisson's ratio , and anisotropy factor . Because the bulk modulus responds linearly to pressure, the material's hardness increases as pressure rises. Additionally, under pressures up to 40 GPa, the optical characteristics of RhTiP, including their reflectivity, absorptivity, conductivity, dielectric constant, refractive index, and loss function, were assessed and discussed. Furthermore, the thermoelectric properties are also studied for the materials and supports the tunning of pressure. This study provides a gateway to how the optoelectronic and transport properties of cubic RhTiP could be tuned by employing external pressure.
利用 DFT 和玻尔兹曼输运理论,我们从原理上计算了半休斯勒化合物 RhTiP 的结构、弹性、电学、光学和热电性能,以研究 0-40 GPa 范围内的压力效应。随着压力的增加,体积和归一化晶格参数降低。除了满足确保化合物 RhTiP "自然稳定性 "的博恩稳定性标准外,零压弹性常数和压力相关弹性常数在 40 GPa 以下均为正值。带状结构计算保证了 RhTiP 的半导体性质,零压时 1.035 eV 的电子带隙证明了这一点。利用压力下的 Voigt-Reuss-Hill (VRH) 平均方案,我们确定了该化合物的体积模量 B $$ B $$、剪切模量 G $$ G $$、杨氏模量 E $$ E $$、普氏比 B / G $$ B/G$$、泊松比 v $$ v $$,以及各向异性因子 A $$ A $$。由于体积模量与压力呈线性关系,因此材料的硬度会随着压力的升高而增加。此外,在高达 40 GPa 的压力下,还评估和讨论了 RhTiP 的光学特性,包括其反射率、吸收率、电导率、介电常数、折射率和损耗函数。此外,还对材料的热电特性进行了研究,并支持压力调谐。这项研究为如何利用外部压力调谐立方氧化钛的光电和传输特性提供了一个途径。
{"title":"Hydrostatic Pressure-Tuning of Opto-Electronic and Thermoelectric Properties Half-Heusler Alloy RhTiP With DFT Analysis","authors":"Aparna Dixit, Arti Saxena, Jisha Annie Abraham, Shubha Dubey, Ramesh Sharma, Saif M. H. Qaid, Ivan Štich, Muhammad Aslam, Anatoly Zetsepin","doi":"10.1002/qua.27482","DOIUrl":"https://doi.org/10.1002/qua.27482","url":null,"abstract":"<div>\u0000 \u0000 <p>Utilizing DFT along with Boltzmann transport theory, the structural, elastic, electrical, optical, and thermoelectric properties of half-Heusler compound RhTiP have been calculated in principle to examine the pressure effect in the range of 0–40 GPa. As pressure increases, the volume and normalized lattice parameter decreased. In addition to satisfying the Born stability criterion, which ensured the compound RhTiP “natural stability,” the zero pressure elastic constants and the pressure-dependent elastic constants are positive up to 40 GPa. The band structure computations guarantee the semiconductor nature of RhTiP, as demonstrated by the presence of electronic band gap of 1.035 eV at zero pressure. Using the Voigt-Reuss-Hill (VRH) averaging scheme under pressure, we have determined the values of this compound's bulk modulus <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>B</mi>\u0000 </mrow>\u0000 <annotation>$$ B $$</annotation>\u0000 </semantics></math>, shear modulus <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>G</mi>\u0000 </mrow>\u0000 <annotation>$$ G $$</annotation>\u0000 </semantics></math>, Young's modulus <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>E</mi>\u0000 </mrow>\u0000 <annotation>$$ E $$</annotation>\u0000 </semantics></math>, Pugh ratio <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>B</mi>\u0000 <mo>/</mo>\u0000 <mi>G</mi>\u0000 </mrow>\u0000 <annotation>$$ B/G $$</annotation>\u0000 </semantics></math>, Poisson's ratio <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>v</mi>\u0000 </mrow>\u0000 <annotation>$$ v $$</annotation>\u0000 </semantics></math>, and anisotropy factor <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>A</mi>\u0000 </mrow>\u0000 <annotation>$$ A $$</annotation>\u0000 </semantics></math>. Because the bulk modulus responds linearly to pressure, the material's hardness increases as pressure rises. Additionally, under pressures up to 40 GPa, the optical characteristics of RhTiP, including their reflectivity, absorptivity, conductivity, dielectric constant, refractive index, and loss function, were assessed and discussed. Furthermore, the thermoelectric properties are also studied for the materials and supports the tunning of pressure. This study provides a gateway to how the optoelectronic and transport properties of cubic RhTiP could be tuned by employing external pressure.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313266","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 dynamic stability of various methane-water clathrate-like cages (CH4@(H2O)n, n = 16, 18, 20, 22), has been analyzed explicitly considering thermal effects by means of ab initio M06-2X/6–31+G*/PCM calculations, which make use of Gaussian basis functions. Starting from the equilibrium filled cage structures, classical, dynamic reaction coordinate (DRC) on the Born–Oppenheimer surface, and semiclassical, Born–Oppenheimer plus harmonic zero-point energy surface (BOMD), molecular dynamics have been carried out. Water molecules have a high tendency to orient covalent O–H bonds tangentially to the hydrophobic surface, thus clathrate-like arrangements are an acceptable model to fully hydrate methane. If the cage size is such as to minimize core repulsion, due to electron cloud overlap, and to maximize host–guest van der Waals attractions, the clathrate-like structures have a life-time of two picoseconds in classical DRC simulations. The inclusion of quantum kinetic energy in BOMD simulations results in less structured cages with a reduced amount of hydrogen bond network. The preferential tangential orientation of the O-H bonds is largely maintained, although few of them point toward the methane for a very short time in BOMD simulations. The reduced configurational space of water molecules hydrating hydrophobic moiety is highlighted, thus any satisfactory molecular modeling has to account for it.
通过使用高斯基函数进行 ab initio M06-2X/6-31+G*/PCM 计算,明确分析了各种甲烷-水凝胶笼(CH4@(H2O)n,n = 16、18、20、22)的动态稳定性,其中考虑到了热效应。从平衡填充笼结构开始,进行了经典的、博恩-奥本海默表面上的动态反应坐标(DRC)和半经典的、博恩-奥本海默加谐波零点能表面(BOMD)的分子动力学计算。水分子非常倾向于将共价 O-H 键定向到与疏水表面相切的方向,因此类似于凝胶体的排列是完全水合甲烷的可接受模型。如果笼子的大小能够使电子云重叠造成的核心排斥力最小化,并使主客范德华吸引力最大化,那么在经典的 DRC 模拟中,类凝胶结构的寿命为两皮秒。在 BOMD 模拟中加入量子动能后,笼状结构的氢键网络数量减少。在 BOMD 模拟中,虽然很少有 O-H 键在很短的时间内指向甲烷,但 O-H 键的优先切向取向基本保持不变。水分子水合疏水分子的构型空间缩小的问题凸显出来,因此任何令人满意的分子建模都必须考虑到这一点。
{"title":"Quantum Chemical Molecular Dynamics Simulations for Methane-Water Cages","authors":"Giuseppe Lanza","doi":"10.1002/qua.27487","DOIUrl":"https://doi.org/10.1002/qua.27487","url":null,"abstract":"<p>The dynamic stability of various methane-water clathrate-like cages (CH<sub>4</sub>@(H<sub>2</sub>O)<sub><i>n</i></sub>, <i>n</i> = 16, 18, 20, 22), has been analyzed explicitly considering thermal effects by means of ab initio M06-2X/6–31+G*/PCM calculations, which make use of Gaussian basis functions. Starting from the equilibrium filled cage structures, <i>classical</i>, dynamic reaction coordinate (DRC) on the Born–Oppenheimer surface, and <i>semiclassical</i>, Born–Oppenheimer plus harmonic zero-point energy surface (BOMD), molecular dynamics have been carried out. Water molecules have a high tendency to orient covalent O–H bonds tangentially to the hydrophobic surface, thus clathrate-like arrangements are an acceptable model to fully hydrate methane. If the cage size is such as to minimize core repulsion, due to electron cloud overlap, and to maximize host–guest van der Waals attractions, the clathrate-like structures have a life-time of two picoseconds in <i>classical</i> DRC simulations. The inclusion of quantum kinetic energy in BOMD simulations results in less structured cages with a reduced amount of hydrogen bond network. The preferential tangential orientation of the O-H bonds is largely maintained, although few of them point toward the methane for a very short time in BOMD simulations. The reduced configurational space of water molecules hydrating hydrophobic moiety is highlighted, thus any satisfactory molecular modeling has to account for it.</p>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qua.27487","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Khuram Shahzad, Shoukat Hussain, Ghulam Abbas Ashraf, Waqar Azeem, Vineet Tirth, Hassan Alqahtani, Ali Algahtani, Tawfiq Al-Mughanam
The use of solar water-splitting technology is anticipated to reduce the disparity between demand and consumption of energy. Herein, CASTEP software is used to investigate the perovskite CsSiX3 (X = Cl and F) materials by applying GGA-PBE exchange–correlation functional. According to structure properties, compounds possess a cubic structure of “pm3m” by using space group 221. The direct band gaps in the CsSiX3 (X = Cl and F) compounds are 1.04 and 1.07 eV, respectively. Measures of the density of states and the partial density of states (PDOS) are being utilized to determine the degree of electron localization in several bands. The compounds' optical characteristics are examined by altering their relation between the dielectric function (DF) scales and the pertinent peak. According to our results, the mechanical properties show that CsSiCl3 is brittle (0.13, 045) and CsSiF3 is ductile (0.32, 2.52) and stable with covalent bonds. Compounds CsSiCl3 and CsSiF3 modulus and elastic constants are {B (8.259, 52.375), E (8.110, 55.082), and G (18.331, 20.790)} and {C11 (13.766, 73.566), C12 (5.506, 41.780), and C44 (10.763, 24.052)} are found, according to mechanical properties. Therefore, such materials can be used for photovoltaic light absorption in the visible spectrum. These materials offer a wide range of possible uses in sensing and solar conversion because compounds combine effectively.
{"title":"First Principle Investigations of Cesium Based Cubic CsSiX3 (X = Cl and F) Perovskites for Solar Conversion Applications: A DFT Study","authors":"Muhammad Khuram Shahzad, Shoukat Hussain, Ghulam Abbas Ashraf, Waqar Azeem, Vineet Tirth, Hassan Alqahtani, Ali Algahtani, Tawfiq Al-Mughanam","doi":"10.1002/qua.27481","DOIUrl":"https://doi.org/10.1002/qua.27481","url":null,"abstract":"<div>\u0000 \u0000 <p>The use of solar water-splitting technology is anticipated to reduce the disparity between demand and consumption of energy. Herein, CASTEP software is used to investigate the perovskite CsSiX<sub>3</sub> (X = Cl and F) materials by applying GGA-PBE exchange–correlation functional. According to structure properties, compounds possess a cubic structure of “pm3m” by using space group 221. The direct band gaps in the CsSiX<sub>3</sub> (X = Cl and F) compounds are 1.04 and 1.07 eV, respectively. Measures of the density of states and the partial density of states (PDOS) are being utilized to determine the degree of electron localization in several bands. The compounds' optical characteristics are examined by altering their relation between the dielectric function (DF) scales and the pertinent peak. According to our results, the mechanical properties show that CsSiCl<sub>3</sub> is brittle (0.13, 045) and CsSiF<sub>3</sub> is ductile (0.32, 2.52) and stable with covalent bonds. Compounds CsSiCl<sub>3</sub> and CsSiF<sub>3</sub> modulus and elastic constants are {<i>B</i> (8.259, 52.375), <i>E</i> (8.110, 55.082), and <i>G</i> (18.331, 20.790)} and {<i>C</i><sub>11</sub> (13.766, 73.566), <i>C</i><sub>12</sub> (5.506, 41.780), and <i>C</i><sub>44</sub> (10.763, 24.052)} are found, according to mechanical properties. Therefore, such materials can be used for photovoltaic light absorption in the visible spectrum. These materials offer a wide range of possible uses in sensing and solar conversion because compounds combine effectively.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313267","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 strain can regulate the electronic properties of transition metal sulfides and enhance their application in ion battery electrode materials. In this article, the potential of single-layer SnS2 as anode material for magnesium ion batteries under shear strain and torsional strain was studied by first-principles calculation. The calculation of adsorption energy shows that the strain does not have a great influence on the structural stability. The band gap of SnS2 calculated by HSE06 is 2.210 eV. When Mg is on the surface of SnS2, the band gap of SnS2 drops to 0.113 eV, which shows quasi-metallic properties. Both strains can regulate the band gap value of SnS2. The diffusion energy barrier of SnS2 after strain is significantly lower than that without strain. After torsion strain, the diffusion barrier of Mg ions on SnS2 is 0.11 eV. The research results provide a theoretical basis for the design of magnesium ion batteries.
{"title":"Computational Study on SnS2 as Anode Material for Magnesium Ion Battery","authors":"Jianmeng Dang, Yanze Li","doi":"10.1002/qua.27478","DOIUrl":"https://doi.org/10.1002/qua.27478","url":null,"abstract":"<div>\u0000 \u0000 <p>The strain can regulate the electronic properties of transition metal sulfides and enhance their application in ion battery electrode materials. In this article, the potential of single-layer SnS<sub>2</sub> as anode material for magnesium ion batteries under shear strain and torsional strain was studied by first-principles calculation. The calculation of adsorption energy shows that the strain does not have a great influence on the structural stability. The band gap of SnS<sub>2</sub> calculated by HSE06 is 2.210 eV. When Mg is on the surface of SnS<sub>2</sub>, the band gap of SnS<sub>2</sub> drops to 0.113 eV, which shows quasi-metallic properties. Both strains can regulate the band gap value of SnS<sub>2</sub>. The diffusion energy barrier of SnS<sub>2</sub> after strain is significantly lower than that without strain. After torsion strain, the diffusion barrier of Mg ions on SnS<sub>2</sub> is 0.11 eV. The research results provide a theoretical basis for the design of magnesium ion batteries.</p>\u0000 </div>","PeriodicalId":182,"journal":{"name":"International Journal of Quantum Chemistry","volume":"124 19","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275067","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}