The electrocatalytic activity of transition-metal-based compounds is closely related to the electronic configuration.However,optimizing the surface electron spin state of catalysts remains a challenge.Here,we develope...The electrocatalytic activity of transition-metal-based compounds is closely related to the electronic configuration.However,optimizing the surface electron spin state of catalysts remains a challenge.Here,we developed a spin-state and delocalized electron regulation method to optimize oxygen evolution reaction(OER)performance by in-situ growth of NiCo_(2)(OH)_(x) using Oswald ripening and coordinating etching process on MXene and plasma treatment.X-ray absorption spectroscopy,magnetic tests and electron paramagnetic resonance reveal that the coupling of NiCo_(2)(OH)_(x) and MXene can induce remarkable spin-state transition of Co^(3+)and transition metal ions electron delocalization,plasma treatment further optimizes the 3 d orbital structure and delocalized electron density.The unique Jahn-Teller phenomenon can be brought by the intermediate spin state(t2 _(g)^(5) e_(g)^(1))of Co^(3+),which benefits from the partial electron occupied egorbitals.This distinct electron configuration(t2_(g)^(5) e_(g)^(1))with unpaired electrons leads to orbital degeneracy,that the adsorption free energy of intermediate species and conductivity were further optimized.The optimized electrocatalyst exhibits excellent OER activity with an overpotential of 268 m V at 10 m A cm^(-2).DFT calculations show that plasma treatment can effectively regulate the d-band center of TMs to optimize the adsorption and improve the OER activity.This approach could guide the rational design and discovery of electrocatalysts with ideal electron configurations in the future.展开更多
We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional el...We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N-electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N-electron systems into two groups. In the first group, the N parties obtain a subset of N-electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N-electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.展开更多
Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti：sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved t...Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti：sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δa（S·I） of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δa（S · I） of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.展开更多
A model of electronic intersupplemental states was presented for calculating the d orbital energies of a distorted octahedral low spin ( S =1/2) n d 5(t 5 2, 2T 2)(n=3, 4, 5) multielectron system...A model of electronic intersupplemental states was presented for calculating the d orbital energies of a distorted octahedral low spin ( S =1/2) n d 5(t 5 2, 2T 2)(n=3, 4, 5) multielectron system, and the 6 dimensional eigenmatrices of two new types in real and complex orbital representations were derived from this electron model forth. In comparison with real and complex orbital methods offered by the hole model, the real and complex orbital methods reported in this paper not only could give directly all the electronic structure parameters for the n d 5(t 5 2, 2T 2) multielectron system, but also showed many other new advantages such as standardization in theory, systematization in method, agreement in calculation and so on.展开更多
基金supported by the National Natural Science Foundation of China(21801090,21831003 and 21621001)the Jilin Scientific and Technological Development Program(20200802003GH)+2 种基金the Scientific Research Project in the Education Department of Jilin Province(JJKH20211044KJ)the Project on Experimental Technique of Jilin University(409020720202)supported by Users with the Excellence Program of Hefei Science Center CAS(2020HSC-UE002)。
文摘The electrocatalytic activity of transition-metal-based compounds is closely related to the electronic configuration.However,optimizing the surface electron spin state of catalysts remains a challenge.Here,we developed a spin-state and delocalized electron regulation method to optimize oxygen evolution reaction(OER)performance by in-situ growth of NiCo_(2)(OH)_(x) using Oswald ripening and coordinating etching process on MXene and plasma treatment.X-ray absorption spectroscopy,magnetic tests and electron paramagnetic resonance reveal that the coupling of NiCo_(2)(OH)_(x) and MXene can induce remarkable spin-state transition of Co^(3+)and transition metal ions electron delocalization,plasma treatment further optimizes the 3 d orbital structure and delocalized electron density.The unique Jahn-Teller phenomenon can be brought by the intermediate spin state(t2 _(g)^(5) e_(g)^(1))of Co^(3+),which benefits from the partial electron occupied egorbitals.This distinct electron configuration(t2_(g)^(5) e_(g)^(1))with unpaired electrons leads to orbital degeneracy,that the adsorption free energy of intermediate species and conductivity were further optimized.The optimized electrocatalyst exhibits excellent OER activity with an overpotential of 268 m V at 10 m A cm^(-2).DFT calculations show that plasma treatment can effectively regulate the d-band center of TMs to optimize the adsorption and improve the OER activity.This approach could guide the rational design and discovery of electrocatalysts with ideal electron configurations in the future.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974020 and 11174039)the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-0031)the Fundamental Research Funds for the Central Universities, China
文摘We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N-electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N-electron systems into two groups. In the first group, the N parties obtain a subset of N-electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N-electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10374103 and 10574143）, and the National Basic Research Program of China （Grant No 2001CB309309）.
文摘Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti：sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δa（S·I） of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δa（S · I） of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.
文摘A model of electronic intersupplemental states was presented for calculating the d orbital energies of a distorted octahedral low spin ( S =1/2) n d 5(t 5 2, 2T 2)(n=3, 4, 5) multielectron system, and the 6 dimensional eigenmatrices of two new types in real and complex orbital representations were derived from this electron model forth. In comparison with real and complex orbital methods offered by the hole model, the real and complex orbital methods reported in this paper not only could give directly all the electronic structure parameters for the n d 5(t 5 2, 2T 2) multielectron system, but also showed many other new advantages such as standardization in theory, systematization in method, agreement in calculation and so on.
