Transmission Electron Microscope (TEM) Technology was used to investigate the effect of 25,100 and 200 mg/kg copper on ultra-structure of root tip and leaf blade of wheat. Result showed that serious damage was found w...Transmission Electron Microscope (TEM) Technology was used to investigate the effect of 25,100 and 200 mg/kg copper on ultra-structure of root tip and leaf blade of wheat. Result showed that serious damage was found with Copper of 25,100 and 200 mg/kg. Plasmolysis,concentrated cytoplasm,chloroplast inflation,lamellar structure disturbance,capsule disappearance and disintegration,mitochondria structures ambiguity and vacuolization were all symptoms under Cu stress. There were positive correlation between concentration of coper stress and the degree of injury,and the degree of injury of copper were different in different organelles. Mitochondria were the most sensitive organelles,and there was patient difference in the same organelles of different parts.展开更多
For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of ...For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons展开更多
The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlatio...The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,展开更多
Electrons are believed to avoid one another in space(correlation) due to the Coulomb repulsion and/or the Pauli exclusion principle.It is shown, using examples of two-electron systems, that indeed the mean electron-el...Electrons are believed to avoid one another in space(correlation) due to the Coulomb repulsion and/or the Pauli exclusion principle.It is shown, using examples of two-electron systems, that indeed the mean electron-electron distance increases in case of the ground electronic state as compared to the independent electron model. It is demonstrated however that there exist excited states, often of low energy, in which the electrons, while having a lot of free physical space(with nuclei being absent), choose to be close to each other in their motion("anticorrelation"), as if they mutually attracted one another. The source of this effect, quantummechanical in nature, is the orthogonality of the eigenfunctions, that forces the electronic wave functions to differ widely, even at the price of short electron-electron distances. There are also excited states with a mixed behaviour, with complex and often intriguing correlation-anticorrelation patterns.展开更多
Comprehension of photon-triggered molecular processes is essential in the study of various important topics in physics,chemistry,and biology.Here we propose a correlated tunneling picture to understand the dissociativ...Comprehension of photon-triggered molecular processes is essential in the study of various important topics in physics,chemistry,and biology.Here we propose a correlated tunneling picture to understand the dissociative ionization process of molecules in intense laser fields based on a quantum model developed in the framework of many-body S-matrix theory including nuclear vibrational motion.In this quantum correlation picture,the single ionization of H_(2)and the subsequent electron-ion recollisioninduced dissociation are considered as an entangled correlated process.It enables us to attribute the interference pattern in the joint-energy spectra to combined effects of single-slit diffraction and multi-slit interference of correlated electron-nuclear wave packets in the time domain.Our work opens a new avenue to understanding molecular dissociative ionization processes in external fields.展开更多
Planar cations or anions can form stacks in crystals or solutions,where the surrounding or environment plays a decisive role as demonstrated in previous studies.However,it remains unclear whether these counterintuitiv...Planar cations or anions can form stacks in crystals or solutions,where the surrounding or environment plays a decisive role as demonstrated in previous studies.However,it remains unclear whether these counterintuitive interactions possess any inherent stability or are thoroughly repulsive if the constraint of environment is removed.In this work,we explored the inherent stability ofπ-πstacking between closed-shell ions of like charges with prototypes derived from experimental studies.The inherent metastability was identified by the characteristic local minima and the transition states preventing their dissociation and verified by ab initio molecular dynamics(AIMD)simulations.The nature of involved interactions was deciphered with the energy decomposition approach based on the block-localized wavefunction method(BLW-ED).Like the conventional neutralπ-πstacking interactions,electron correlation is the most attractive energy component.But it is overturned by the Coulombic repulsion between net charges for all modes of dimerization,resulting in the overall repulsive inter-cation or anion in-teractions.Contributions from van der Waals interactions were also observed in the reduced density gradient analysis.The origin of the metastability was elucidated by examining the contributions of individual physical factors to the well-depths.The inherent metastability originates from the electron correlation,which dramatically increases due to the enhanced overlap between ions from a transition state to its corresponding minimum.展开更多
The metal-to-insulator transition(MIT) as usually achieved in 3d-orbital transitional metal(TM) compounds opens up a new paradigm in correlated electronics via triggering abrupt variations in their transportation prop...The metal-to-insulator transition(MIT) as usually achieved in 3d-orbital transitional metal(TM) compounds opens up a new paradigm in correlated electronics via triggering abrupt variations in their transportation properties.Compared to such 3d-orbital TM compounds,the MIT within the platinum group(Pg) element compounds based on the 4d-and 5d-orbital configurations is more complicated,owing to their elevation in the spinorbit coupling and meanwhile weakened intra-atomic Coulomb repulsions.This brings in a new freedom to regulate the balance in their metallic or semiconductive orbital configurations,while their MIT properties can be potentially combined with their spintronic properties to enable new electronic applications.Herein,we review the electronic transport and MIT behaviors within the existing family of Pg-containing compounds,particularly those showing first-order MIT behaviors that can be useful in correlated electronics.It is also hoped that summarizing the presently reported Pg-containing MIT compounds will lead to the discovery of more new material families and/or new mechanisms associated with the Pg-containing compounds showing MIT properties.展开更多
The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47)...The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.展开更多
基金Supported by Scientific and Technological Fund from China University of Mining and Technology (D200402)~~
文摘Transmission Electron Microscope (TEM) Technology was used to investigate the effect of 25,100 and 200 mg/kg copper on ultra-structure of root tip and leaf blade of wheat. Result showed that serious damage was found with Copper of 25,100 and 200 mg/kg. Plasmolysis,concentrated cytoplasm,chloroplast inflation,lamellar structure disturbance,capsule disappearance and disintegration,mitochondria structures ambiguity and vacuolization were all symptoms under Cu stress. There were positive correlation between concentration of coper stress and the degree of injury,and the degree of injury of copper were different in different organelles. Mitochondria were the most sensitive organelles,and there was patient difference in the same organelles of different parts.
基金National Natural Science Foundation of ChinaScience Foundation of Tsinghua University.
文摘For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons
基金Project supported by the National Natural Science Foundation of Chinathe Special Science Foundation of the State Education Commission of China.
文摘The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,
文摘Electrons are believed to avoid one another in space(correlation) due to the Coulomb repulsion and/or the Pauli exclusion principle.It is shown, using examples of two-electron systems, that indeed the mean electron-electron distance increases in case of the ground electronic state as compared to the independent electron model. It is demonstrated however that there exist excited states, often of low energy, in which the electrons, while having a lot of free physical space(with nuclei being absent), choose to be close to each other in their motion("anticorrelation"), as if they mutually attracted one another. The source of this effect, quantummechanical in nature, is the orthogonality of the eigenfunctions, that forces the electronic wave functions to differ widely, even at the price of short electron-electron distances. There are also excited states with a mixed behaviour, with complex and often intriguing correlation-anticorrelation patterns.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.12274273,12304379,11925405+2 种基金12304304)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302101)the Natural and Science Foundation of Top Talent of SZTU(Grant No.GDRC202202)。
文摘Comprehension of photon-triggered molecular processes is essential in the study of various important topics in physics,chemistry,and biology.Here we propose a correlated tunneling picture to understand the dissociative ionization process of molecules in intense laser fields based on a quantum model developed in the framework of many-body S-matrix theory including nuclear vibrational motion.In this quantum correlation picture,the single ionization of H_(2)and the subsequent electron-ion recollisioninduced dissociation are considered as an entangled correlated process.It enables us to attribute the interference pattern in the joint-energy spectra to combined effects of single-slit diffraction and multi-slit interference of correlated electron-nuclear wave packets in the time domain.Our work opens a new avenue to understanding molecular dissociative ionization processes in external fields.
基金support from the Natural Science Foundation of China(No.22073060)support from the Natural Science Foundation of China(No.22273054)This work was performed in part at the Joint School of Nanoscience and Nanoengineering,a member of the National Nanotechnology Coordinated Infrastructure(NNCI),which is supported by the US National Science Foundation(Grant ECCS-2025462).
文摘Planar cations or anions can form stacks in crystals or solutions,where the surrounding or environment plays a decisive role as demonstrated in previous studies.However,it remains unclear whether these counterintuitive interactions possess any inherent stability or are thoroughly repulsive if the constraint of environment is removed.In this work,we explored the inherent stability ofπ-πstacking between closed-shell ions of like charges with prototypes derived from experimental studies.The inherent metastability was identified by the characteristic local minima and the transition states preventing their dissociation and verified by ab initio molecular dynamics(AIMD)simulations.The nature of involved interactions was deciphered with the energy decomposition approach based on the block-localized wavefunction method(BLW-ED).Like the conventional neutralπ-πstacking interactions,electron correlation is the most attractive energy component.But it is overturned by the Coulombic repulsion between net charges for all modes of dimerization,resulting in the overall repulsive inter-cation or anion in-teractions.Contributions from van der Waals interactions were also observed in the reduced density gradient analysis.The origin of the metastability was elucidated by examining the contributions of individual physical factors to the well-depths.The inherent metastability originates from the electron correlation,which dramatically increases due to the enhanced overlap between ions from a transition state to its corresponding minimum.
基金financially supported by the National Key Research and Development Program of China (No.2021YFA0718900)the National Natural Science Foundation of China (Nos.62074014 and 52073090)the support by Xiao Mi scholar project。
文摘The metal-to-insulator transition(MIT) as usually achieved in 3d-orbital transitional metal(TM) compounds opens up a new paradigm in correlated electronics via triggering abrupt variations in their transportation properties.Compared to such 3d-orbital TM compounds,the MIT within the platinum group(Pg) element compounds based on the 4d-and 5d-orbital configurations is more complicated,owing to their elevation in the spinorbit coupling and meanwhile weakened intra-atomic Coulomb repulsions.This brings in a new freedom to regulate the balance in their metallic or semiconductive orbital configurations,while their MIT properties can be potentially combined with their spintronic properties to enable new electronic applications.Herein,we review the electronic transport and MIT behaviors within the existing family of Pg-containing compounds,particularly those showing first-order MIT behaviors that can be useful in correlated electronics.It is also hoped that summarizing the presently reported Pg-containing MIT compounds will lead to the discovery of more new material families and/or new mechanisms associated with the Pg-containing compounds showing MIT properties.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1832126 and 11874051)the National Key Research and Development Program of China(Grant No.2017YFA0402300)。
文摘The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.
