Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the closed-orbit theory and classical perturbation theory, we calculate the scaled recurrence spec...Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the closed-orbit theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases; others persist till much higher f . As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.展开更多
Using core-scattered closed-orbit theory and region-splitting iterative method, we calculated the scaled recurrence spectra of helium atom in parallel electric and magnetic fields. Closed orbits in the corresponding c...Using core-scattered closed-orbit theory and region-splitting iterative method, we calculated the scaled recurrence spectra of helium atom in parallel electric and magnetic fields. Closed orbits in the corresponding classical system have also been obtained. When we search the closed orbits, in order to remove the Coulomb singularity of the classical Hamiltonian motion equations, we implement the Kustaanheimo-Stiefel transformation, which transforms the system from a three-dimensional to a four-dimensional one. The Fourier transformed spectrum of helium atom has allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The results are compared with those of the hydrogen case, which shows that the core-scattered effects play an important role in the recurrence spectra of the multi-electron Rydberg atom.展开更多
Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled ene...Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled energies below ionization threshold. The results show that with the increase of the scaled energy, the number of the closed orbit increases greatly. Some of the orbits are created by the bifurcation of the perpendicular orbit. This case is quite similar to the Rydberg atom in an electric field. When the scaled energy increases furthermore, chaotic orbits appear. This study provides a different perspective on the dynamical behavior of the Rydberg atom near a metal surface.展开更多
目的:确定1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱结构及其优势构象,并探讨其抗HIV-1病毒活性。方法:制备1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱,并利用红外光谱,核磁波谱技术和PM6半经典计算等方法对其结构进行解...目的:确定1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱结构及其优势构象,并探讨其抗HIV-1病毒活性。方法:制备1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱,并利用红外光谱,核磁波谱技术和PM6半经典计算等方法对其结构进行解析;采用HIV-l_(ⅢB)/TZM-bl细胞指示系统测定其抗HIV-1病毒活性。结果:光谱分析表明1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱新化合物具有烯胺-烯胺结构特征,并归属了所有碳原子和氢质子化学位移;PM6研究表明1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱烯胺-烯胺和亚胺-亚胺构型的生成热分别为-4 168.415 k J·mol^(-1)和-4 150.080 k J·mol^(-1),烯胺-烯胺构型在能量上更有利,并确立了其优势构象,分子内氢键使其更为稳定,与光谱分析结果一致;新化合物显示了较强的抗艾滋病毒活性,可能作用在病毒感染细胞的进入阶段。结论:1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱以烯胺-烯胺构型存在,具有一定抗艾滋病毒活性。展开更多
文摘Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the closed-orbit theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases; others persist till much higher f . As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.
文摘Using core-scattered closed-orbit theory and region-splitting iterative method, we calculated the scaled recurrence spectra of helium atom in parallel electric and magnetic fields. Closed orbits in the corresponding classical system have also been obtained. When we search the closed orbits, in order to remove the Coulomb singularity of the classical Hamiltonian motion equations, we implement the Kustaanheimo-Stiefel transformation, which transforms the system from a three-dimensional to a four-dimensional one. The Fourier transformed spectrum of helium atom has allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The results are compared with those of the hydrogen case, which shows that the core-scattered effects play an important role in the recurrence spectra of the multi-electron Rydberg atom.
基金supported by National Natural Science Foundation of China under Grant No.10604045the Doctoral Scientific Research Startup Foundation of Ludong University under Grant No.202-23000301
文摘Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled energies below ionization threshold. The results show that with the increase of the scaled energy, the number of the closed orbit increases greatly. Some of the orbits are created by the bifurcation of the perpendicular orbit. This case is quite similar to the Rydberg atom in an electric field. When the scaled energy increases furthermore, chaotic orbits appear. This study provides a different perspective on the dynamical behavior of the Rydberg atom near a metal surface.
文摘目的:确定1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱结构及其优势构象,并探讨其抗HIV-1病毒活性。方法:制备1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱,并利用红外光谱,核磁波谱技术和PM6半经典计算等方法对其结构进行解析;采用HIV-l_(ⅢB)/TZM-bl细胞指示系统测定其抗HIV-1病毒活性。结果:光谱分析表明1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱新化合物具有烯胺-烯胺结构特征,并归属了所有碳原子和氢质子化学位移;PM6研究表明1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱烯胺-烯胺和亚胺-亚胺构型的生成热分别为-4 168.415 k J·mol^(-1)和-4 150.080 k J·mol^(-1),烯胺-烯胺构型在能量上更有利,并确立了其优势构象,分子内氢键使其更为稳定,与光谱分析结果一致;新化合物显示了较强的抗艾滋病毒活性,可能作用在病毒感染细胞的进入阶段。结论:1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖棉酚Schiff碱以烯胺-烯胺构型存在,具有一定抗艾滋病毒活性。
