Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite ano...Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.展开更多
This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive...This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive the PMFs of K^+-Cl^- ion pair from 673 to 1273 K in low-density water(0.10-0.60 g/cm).The PMF results show that the contact ion-pair(CIP) state is the one most energetically favored for a K^+-Cl^- ion pair.The association constants of the K^+-Cl^- ion pair are calculated from the PMFs,indicating that the K^+-Cl^- ion pair is thermodynamically stable.It gets more stable as T increases or water density decreases.The microstructures of the K^+-Cl^- ion pair in the CIP and solvent-shared ion-pair states are characterized in detail.Moreover,we explore the structures and stabilities of the KCl-Au(I)/Cu(I) complexes by using quantum mechanical calculations.The results reveal that these complexes can remain stable for T up to1273 K,which indicates that KCl may act as a ligand complexing ore-forming metals in hydrothermal fluids.展开更多
This paper summarizes significant progress in quantifying organic substituent effects in the last 20 years. The main content is as follows： （1） The principle of electronegativity equalization has gained wide accept...This paper summarizes significant progress in quantifying organic substituent effects in the last 20 years. The main content is as follows： （1） The principle of electronegativity equalization has gained wide acceptance, and has been used to calculate the intramolecular charge distribution and inductive effect of groups. A valence electrons equalization method was proposed to compute the molecular electronegativity on the basis of geometric mean method, harmonic mean method, and weighted mean method. This new calculation method further extended the application of the principle of electronegativity equalization. （2） A scale method was established for experimentally determining the electrophilic and nucleophilic ability of reagents, in which benzhydryliumions and quinone methides were taken as the reference compounds, and the research field was extended to the gas phase conditions, organometallic reaction and radicals system. Moreover, the nucleophilicity parameters N and electro- philicity parameters E for a series of reagents were obtained. The definition and quantitative expression of electrophilicity in- dex co and nucleophilicity index co were proposed theoretically, and the correlation between the parameters from experimental determination and the indexes from theoretical calculation was also investigated. （3） The polarizability effect parameter was initially calculated by empirical method and further developed by quantum chemistry method. Recently, the polarizability ef- fect index of alkyl （PEI） and groups （PEIx） were proposed by statistical method, and got wide applications in explaining and estimating gas-phase acidity and basicity, ionization energy, enthalpy of formation, bond energy, reaction rate, water solubility and chromatographic retention for organic compounds. （4） The excited-state substituent constant Crcc obtained directly from the UV absorption energy data of substituted benzenes, is different from the polar constants in molecular ground state and the radical spin-del展开更多
All of the experimentally known electronic states of the Cr group metal monoxides(Cr O,Mo O,and WO)have been presented in the paper.The optical spectra of the Cr O molecule have been investigated in the gas phase thro...All of the experimentally known electronic states of the Cr group metal monoxides(Cr O,Mo O,and WO)have been presented in the paper.The optical spectra of the Cr O molecule have been investigated in the gas phase through a combination of the laser-induced fluorescence(LIF)excitation and single-vibronic-level(SVL)emission spectroscopy in the supersonic expansion.The rotational constants of the vibronic electronic states,including X^(5)Π_(-1)(v=0–3),B^(5)Π_(-1)(v=0–10),and B~5Π_1(v=1,5),and the vibrational constants of the spin–orbit components X^(5)Π_(-1,0,1)have been obtained.The molecular constants of the Mo O and WO molecules have been summarized by reviewing the previous spectroscopic studies,and a comprehensive energy level diagram of the Cr group metal monoxides has been constructed.By comparing the electronic configurations,bond lengths,and vibrational frequencies of all the transition metal monoxides in the ground electronic state,the significance of the relativistic effect in the bonding of the 5d transition metal monoxides has been discussed.The related spectroscopic data of the Cr O molecule are available at https://doi.org/10.57760/sciencedb.j00113.00085.展开更多
采用Davidson修正的内收缩多参考组态相互作用方法(icMRCI+Q)结合Dunning等的相关一致基计算了PS自由基X2Π态势能曲线.利用三阶Douglas-Kroll Hamilton近似结合cc-pV5Z相对论收缩基进行了相对论修正计算.利用aug-cc-pCV5Z基组对势能曲...采用Davidson修正的内收缩多参考组态相互作用方法(icMRCI+Q)结合Dunning等的相关一致基计算了PS自由基X2Π态势能曲线.利用三阶Douglas-Kroll Hamilton近似结合cc-pV5Z相对论收缩基进行了相对论修正计算.利用aug-cc-pCV5Z基组对势能曲线进行了核价相关修正计算,并将总能量外推至完全基组极限.拟合得到了X2Π态的主要光谱常数Re,ωe,ωexe,ωeye,Be,αe和De,与实验结果符合较好.利用Breit-Pauli算符,研究了旋轨耦合效应对势能曲线的影响,得到了两条态的势能曲线.详细分析了在旋轨耦合计算中,核电子相关与冻结核近似对电子结构和光谱性质的影响.在icMRCI+Q/56+DK+CV+SO理论水平上得到了两个态的主要光谱常数Te,Re,ωe,ωexe,ωeye,Be和αe,结果与实验结果一致.在平衡位置处,本文的X2Π态旋轨耦合能量分裂值为323.73 cm 1,与实验结果321.93 cm 1较为一致.通过求解双原子分子核运动的径向Schrdinger方程,找到了无转动PS自由基X2Π态及其两个态的全部振动态,还分别计算了它们相应的振动能级和惯性转动常数等分子常数,这些结果与已有的实验值一致.展开更多
基金supported by the National Natural Science Foundation of China(T2322015,22209094,22209093,and 22109086)the National Key Research and Development Program(2021YFB2500300)+2 种基金the Open Research Fund of CNMGE Platform&NSCC-TJOrdos-Tsinghua Innovative&Collaborative Research Program in Carbon Neutralitythe Tsinghua University Initiative Scientific Research Program。
文摘Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.
基金HUANG Ying was supported by the Natural Science Foundation of Hunan Province,China (11JJ5065)Hunan College Student Research Study,Innovative Experiments,China (Xiang Jiao Tong [2011] 272)+4 种基金"Twelfth Five-Year" Key Discipline of Hunan University of Chinese Medicine-Pharmaceutical Analysis Science,ChinaZHANG Peng-Fei was supported by the Funds from the Major New Drug Discovery Science and Technology,China (2012ZX09303013-06)National Natural Science Foundation of China (81272609)Public Health Department of Hunan Scientific Research Foundation,China (B2010-004)LIU Liang-Hong was supported by the 2012 Innovation Program of Hunan University of Chinese Medicine for Postgraduate Students,China (2012cx07)~~
基金National Science Foundation of China(Nos.41222015,41273074,41425009,and 41572027)Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)+1 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of P.R.China (No.201228)Newton International Fellowship Program and the financial support from the State Key Laboratory at Nanjing University
文摘This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive the PMFs of K^+-Cl^- ion pair from 673 to 1273 K in low-density water(0.10-0.60 g/cm).The PMF results show that the contact ion-pair(CIP) state is the one most energetically favored for a K^+-Cl^- ion pair.The association constants of the K^+-Cl^- ion pair are calculated from the PMFs,indicating that the K^+-Cl^- ion pair is thermodynamically stable.It gets more stable as T increases or water density decreases.The microstructures of the K^+-Cl^- ion pair in the CIP and solvent-shared ion-pair states are characterized in detail.Moreover,we explore the structures and stabilities of the KCl-Au(I)/Cu(I) complexes by using quantum mechanical calculations.The results reveal that these complexes can remain stable for T up to1273 K,which indicates that KCl may act as a ligand complexing ore-forming metals in hydrothermal fluids.
基金financially supported by the National Natural Science Foundation of China (21272063, 21072053, 20772028, 20472019 and20172043)the Scientific Research Fund of Hunan Provincial Education Department (10K025)
文摘This paper summarizes significant progress in quantifying organic substituent effects in the last 20 years. The main content is as follows： （1） The principle of electronegativity equalization has gained wide acceptance, and has been used to calculate the intramolecular charge distribution and inductive effect of groups. A valence electrons equalization method was proposed to compute the molecular electronegativity on the basis of geometric mean method, harmonic mean method, and weighted mean method. This new calculation method further extended the application of the principle of electronegativity equalization. （2） A scale method was established for experimentally determining the electrophilic and nucleophilic ability of reagents, in which benzhydryliumions and quinone methides were taken as the reference compounds, and the research field was extended to the gas phase conditions, organometallic reaction and radicals system. Moreover, the nucleophilicity parameters N and electro- philicity parameters E for a series of reagents were obtained. The definition and quantitative expression of electrophilicity in- dex co and nucleophilicity index co were proposed theoretically, and the correlation between the parameters from experimental determination and the indexes from theoretical calculation was also investigated. （3） The polarizability effect parameter was initially calculated by empirical method and further developed by quantum chemistry method. Recently, the polarizability ef- fect index of alkyl （PEI） and groups （PEIx） were proposed by statistical method, and got wide applications in explaining and estimating gas-phase acidity and basicity, ionization energy, enthalpy of formation, bond energy, reaction rate, water solubility and chromatographic retention for organic compounds. （4） The excited-state substituent constant Crcc obtained directly from the UV absorption energy data of substituted benzenes, is different from the polar constants in molecular ground state and the radical spin-del
基金the National Key R&D Program of China(Grant No.2022YFA1602500)the National Natural Science Foundation of China(Grant No.12027809)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030900)。
文摘All of the experimentally known electronic states of the Cr group metal monoxides(Cr O,Mo O,and WO)have been presented in the paper.The optical spectra of the Cr O molecule have been investigated in the gas phase through a combination of the laser-induced fluorescence(LIF)excitation and single-vibronic-level(SVL)emission spectroscopy in the supersonic expansion.The rotational constants of the vibronic electronic states,including X^(5)Π_(-1)(v=0–3),B^(5)Π_(-1)(v=0–10),and B~5Π_1(v=1,5),and the vibrational constants of the spin–orbit components X^(5)Π_(-1,0,1)have been obtained.The molecular constants of the Mo O and WO molecules have been summarized by reviewing the previous spectroscopic studies,and a comprehensive energy level diagram of the Cr group metal monoxides has been constructed.By comparing the electronic configurations,bond lengths,and vibrational frequencies of all the transition metal monoxides in the ground electronic state,the significance of the relativistic effect in the bonding of the 5d transition metal monoxides has been discussed.The related spectroscopic data of the Cr O molecule are available at https://doi.org/10.57760/sciencedb.j00113.00085.
文摘采用Davidson修正的内收缩多参考组态相互作用方法(icMRCI+Q)结合Dunning等的相关一致基计算了PS自由基X2Π态势能曲线.利用三阶Douglas-Kroll Hamilton近似结合cc-pV5Z相对论收缩基进行了相对论修正计算.利用aug-cc-pCV5Z基组对势能曲线进行了核价相关修正计算,并将总能量外推至完全基组极限.拟合得到了X2Π态的主要光谱常数Re,ωe,ωexe,ωeye,Be,αe和De,与实验结果符合较好.利用Breit-Pauli算符,研究了旋轨耦合效应对势能曲线的影响,得到了两条态的势能曲线.详细分析了在旋轨耦合计算中,核电子相关与冻结核近似对电子结构和光谱性质的影响.在icMRCI+Q/56+DK+CV+SO理论水平上得到了两个态的主要光谱常数Te,Re,ωe,ωexe,ωeye,Be和αe,结果与实验结果一致.在平衡位置处,本文的X2Π态旋轨耦合能量分裂值为323.73 cm 1,与实验结果321.93 cm 1较为一致.通过求解双原子分子核运动的径向Schrdinger方程,找到了无转动PS自由基X2Π态及其两个态的全部振动态,还分别计算了它们相应的振动能级和惯性转动常数等分子常数,这些结果与已有的实验值一致.
