In this study,single-particle energy was examined using the finite difference method by taking 208Pb as an example.If the first derivative term in the spherical Dirac equation is discretized using a three-point formul...In this study,single-particle energy was examined using the finite difference method by taking 208Pb as an example.If the first derivative term in the spherical Dirac equation is discretized using a three-point formula,a one-to-one correspondence occurs between the physical and spurious states.Although these energies are exactly the same,the wave functions of the spurious states exhibit a much faster staggering than those of the physical states.Such spurious states can be eliminated when applying the finite difference method by introducing an extra Wilson term into the Hamiltonian.Furthermore,it was also found that the number of spurious states can be reduced if we improve the accuracy of the numerical differential formula.The Dirac equation is then solved in a momentum space in which there is no differential operator,and we found that the spurious states can be completely avoided in the momentum space,even without an extra Wilson term.展开更多
The electronic structure of nitrogen trifluoride was investigated by combining the high-resolution electron momentum spectroscopy with the high-level calculations. The experimental binding energy spectra and the momen...The electronic structure of nitrogen trifluoride was investigated by combining the high-resolution electron momentum spectroscopy with the high-level calculations. The experimental binding energy spectra and the momentum distributions of each orbital were compared with the results of Hartree-Fock, density functional theory （DFT）, and symmetry-adapted- cluster configuration-interaction （SAC-CI） methods. SAC-CI and DFT-B3LYP with the aug-cc-pVTZ basis set can well reproduce the binding energy spectra and the observed momentum distributions of the valence orbitals except 1 a2 and 4e orbitals. It was found that the calculated momentum distributions using DFT-B3LYP are even better than those using the high-level SAC-CI method.展开更多
The C_(4)H_(10) molecule has been studied by high resolution(e,2e)spectrometer at a total energy of 1200eV and using symmetric non-coplanar kinematics.The binding energy spectra ranging up to 32eV are measured at out-...The C_(4)H_(10) molecule has been studied by high resolution(e,2e)spectrometer at a total energy of 1200eV and using symmetric non-coplanar kinematics.The binding energy spectra ranging up to 32eV are measured at out-of-plane azimuthal angles from 0° to 22° corresponding to target electron momentum from about 0.1 to 1.8 a.u.The binding energy spectra and electron momentum distributions obtained for the valence orbitals are compared with the theoretical result calculated by using restricted Hartree-Fock and density functional theory methods.The agreement between theory and experiment of orbital electron momentum distributions is generally good.展开更多
基金partly supported by the National Natural Science Foundation of China(No.11875070)the Natural Science Foundation of Anhui Province(No.1908085MA16)
文摘In this study,single-particle energy was examined using the finite difference method by taking 208Pb as an example.If the first derivative term in the spherical Dirac equation is discretized using a three-point formula,a one-to-one correspondence occurs between the physical and spurious states.Although these energies are exactly the same,the wave functions of the spurious states exhibit a much faster staggering than those of the physical states.Such spurious states can be eliminated when applying the finite difference method by introducing an extra Wilson term into the Hamiltonian.Furthermore,it was also found that the number of spurious states can be reduced if we improve the accuracy of the numerical differential formula.The Dirac equation is then solved in a momentum space in which there is no differential operator,and we found that the spurious states can be completely avoided in the momentum space,even without an extra Wilson term.
基金supported by the National Natural Science Foundation of China(Grant No.11174175)the Tsinghua University Initiative Scientific Research Program,China
文摘The electronic structure of nitrogen trifluoride was investigated by combining the high-resolution electron momentum spectroscopy with the high-level calculations. The experimental binding energy spectra and the momentum distributions of each orbital were compared with the results of Hartree-Fock, density functional theory （DFT）, and symmetry-adapted- cluster configuration-interaction （SAC-CI） methods. SAC-CI and DFT-B3LYP with the aug-cc-pVTZ basis set can well reproduce the binding energy spectra and the observed momentum distributions of the valence orbitals except 1 a2 and 4e orbitals. It was found that the calculated momentum distributions using DFT-B3LYP are even better than those using the high-level SAC-CI method.
基金Supported by the National Natural Science Foundation of China under Grant No.19874037.
文摘The C_(4)H_(10) molecule has been studied by high resolution(e,2e)spectrometer at a total energy of 1200eV and using symmetric non-coplanar kinematics.The binding energy spectra ranging up to 32eV are measured at out-of-plane azimuthal angles from 0° to 22° corresponding to target electron momentum from about 0.1 to 1.8 a.u.The binding energy spectra and electron momentum distributions obtained for the valence orbitals are compared with the theoretical result calculated by using restricted Hartree-Fock and density functional theory methods.The agreement between theory and experiment of orbital electron momentum distributions is generally good.
