CO在Cu/ZnO上吸附的簇模型研究

采用DFT方法和HF方法对CO在Cu／ZnO催化剂上的Zn（Ⅱ）和Cu（Ⅰ）表面位上的吸附行为进行了比较研究.结果表明：HF方法给出了较弱的M-CO（M＝Zn（Ⅱ），Cu（Ⅰ））表面吸附键描述，但无法正确预测其强弱顺序，MP2方法与DFT方法则给出与实验事实一致的描述.文章还对CO／铜基催化剂吸附体系的IR光谱进行了合理的理论预测

Bonding of Alkali-mercury and Alkali-lead Clusters

Relativistic density-Functional calculations on Free Hg2, Hg4, Hg8, Pb2 and Pb4 clusters, and those clusters embedded in an alkali (A) atom surrounding are reported.Heavy metal-metal (M-M) distances, binding energies and eFFective charges have been cal culated.The Hg-Hg distance in the weakly bound Free clusters is over 330 pm.Upon embedding in an alkali surrounding, the bonding is strengthened; the bond lengths are re duced For square planar Hg4 to below 300 pm.The bonding in the hypothetical tetrahedral alkali-mercury cluster appear to be quite diFFerent, where Hg4 win undergo a transition to Four Hg1.This explains the strict preFerence of square over the tetrahedral geomety of Hg4 clusters in arnalgams.Pb4 is predicted to be stable in a pure cluster and does not show signiFicanly diFFerent bonding Feature in the lead-alkali crystal.The eFFective charges on Hg and Pb are calculated to be -0.4 and -0.6, respectively.The bonding characteristics are also examined by calculation of the M4-An interaction energies.The amalgamation energies lie in the range of 50 to 70 kJ/molHg.The Formation energy of alkall-Pb is up to 150 kJ/molPb, much stronger than that of alkali-Hg

Bonding of Alkali-mercury and Alkali-lead Clusters

Relativistic density-functional calculations on free Hg-2, Hg(4)m Hg-6 Pb-2 and Pb-4 clusters, and those clusters embedded in an alkali (A) atom surrounding are reported. Heavy metal-metal (M-M) distances, binding energies and effective charges have been calculated. The Hg-Hg distance in the weakly bound free clusters is over 330 pm. Upon embedding in an alkali surrounding, the bonding is strenghthened; the bond lengths are reduced for square planar Hg-4 to below 300 pm. The bonding in the hypothetical tetrahedrat alkali mecury cluster appear to be quite different. Where Hg-4 will undergo a transition to four Hg-2. This explains the strict preference of suare over the terrahedral geometry of Hg-4 significantly different bonding feature in the lead-alkali crystal. The effective charges on Hg and Pb are calculated to be 0.4 and 0.6, respectively. The bonding characteristics are also examined by calculation of the M-4-A(n) interaction energies. The amalgamation energies lie in the range of 50 to 70 kJ/molHg. the formation energy of alkali-Pb is up to 150 kJ/molPb, much stronger than that of alkali-Hg

On the ConFiguration of the [NiH_4] Complex in Cubic Mg_2NiH_4 Structure

用相对论密度泛函法研究了立方晶体Mg2nIH4结构中复合体[nIH4]的几何构型.晶体的环境用一个“切断”（CuT-Off）的MAdElung势来模拟.计算中分别假设了一个平面四边形nIH和一个四面体nIH的构型.对于平面四边形构型，计算的nI-H键长及力常数与实验值相符；但对四面体计算的键长太短而力常数太大.研究结果表明；立方Mg2nIH4结构中对复合体[nIH4]的选择是平面四边形构型，而不是四面体.The conFiguration of the [N1H4] complex in cubic Mg2NiH4 structure has been investigated by using relativistic density-Functional method The crystalline environment was simulated by a cut-ofF type Made1ung potential.A square planar conFiguration of NiHi and a tetrahedral conFiguration of NiH are assumed, respectively in the calculations.For the square planar conFigurati0n, a good agreement of the calculated bond length and Force constant with experimental ones was obtained.However, the calculation on the tetrahedral conFiguration yielded too short Ni-H bond length and too large Ni-H Force constant.The comparison between the ca1culated results and experimenta1 ones gives a clear preFerence of the square NiH conFiguration over the tetrahedral NiH conFiguration in the cubic Mg2NiH4 structure.国家教育委员会留学回国人员经费资

相对论密度泛函法对CN~－在铜和银电极上振动频率的研究

对ＣＮ￣－在铜和银电极上的吸附性质进行了相对论密度泛函簇模型计算。结果表明，电场微扰方法可以描述ＣＮ￣－在铜和银电极上吸附的表面现象，电极势诱导的频率移动被理解为Ｓｔａｒｋ效应所引起；内振动模式Ｍ－ＣＮ和Ｃ－Ｎ的耦合对电位诱导的Ｃ－Ｎ振动频率变化的大小起重要作用。计算所得的由Ｓｔａｒｋ效应所引起Ｃ－Ｎ振动频率变化的斜率与实验结果相符

A Relativistic Density-Functional Investigation of Vibrational Frequencies of CN￣- on Cu and Ag Electrodes

对Cn￣-在铜和银电极上的吸附性质进行了相对论密度泛函簇模型计算。结果表明，电场微扰方法可以描述Cn￣-在铜和银电极上吸附的表面现象，电极势诱导的频率移动被理解为STArk效应所引起；内振动模式M-Cn和C-n的耦合对电位诱导的C-n振动频率变化的大小起重要作用。计算所得的由STArk效应所引起C-n振动频率变化的斜率与实验结果相符。Abstract Potential Dependence,Vibrational Frequency,copper-electrode,Silver-electrode,Relativistic density-Functional calculationAcknowledgements This work was supported by the National Natural Science Foundationof China and ChinaPostdoctoral Science Foundation

On the configuration of the [NiH4] complex in cubic Mg2NiH4 structure

The configuration of the [NiH4] complex in cubic Mg2NiH4 structure has been investigated by using relativistic density-functional method, The crystalline environment was simulated by a cut-off type Madelung potential, A square planar configuration of NiH42- and a tetrahedral configuration of NiH44- are assumed, respectively in the calculations. For the square planar configuration, a good agreement of the calculated bond length and force constant with experimental ones was obtained. However, the calculation on the tetrahedral configuration yielded too short Ni-H bond length and too large Ni-H farce constant. The comparison between the calculated results and experimental ones gives a clear preference of the square NiH42- configuration over the tetrahedral NiH44- configuration in the cubic Mg2NiH4 structure

A Relativistic Density-Functional Investigation of Vibrational Frequencies of CN￣- on Cu and Ag Electrodes

对ＣＮ￣－在铜和银电极上的吸附性质进行了相对论密度泛函簇模型计算。结果表明，电场微扰方法可以描述ＣＮ￣－在铜和银电极上吸附的表面现象，电极势诱导的频率移动被理解为Ｓｔａｒｋ效应所引起；内振动模式Ｍ－ＣＮ和Ｃ－Ｎ的耦合对电位诱导的Ｃ－Ｎ振动频率变化的大小起重要作用。计算所得的由Ｓｔａｒｋ效应所引起Ｃ－Ｎ振动频率变化的斜率与实验结果相符。Abstract Potential Dependence,Vibrational Frequency,copper-electrode,Silver-electrode,Relativistic density-functional calculationAcknowledgements This work was supported by the National Natural Science Foundationof China and ChinaPostdoctoral Science Foundation.作者联系地址：厦门大学化学系Author's Address: Chemistry Department,Xiamen University,Xiamen 36100

Cluster Modelling of CO Chemisorption on Cu/ZnO

The Chemisorption of CO on the Zn(II) and Cu(I) sites presenting on the Cu/ZnO(0001) surface has been studied with DFT method and HF method, While HF calculations underestimate the M-CO bonding, and give a wrong order of the M-CO(M=Zn(II), Cu(I)) bond strength MP2 and DFT calculations give a rather realistic description for the chemisorption systems, Our theoretical prediction of IR spectroscopy of the CO/Cu/ZnO system is in good accordance with the experimental outcome

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors