High-precision Calculations For Three-electron Atomic Systems In Magnetic Fields

Since the discovery of the existence of a strong magnetic field of dense stars surface, the original research data is not suitable for astronomical observation for atomic and molecular system without a magnetic field. In the past thirty years, along with the demand of the spectroscopic data in astrophysics, the theoretical calculation in a strong magnetic field has been the subject of computational physics for the atomic and molecular system theory. This paper first introduced that the arbitrary bound states of four-body atomic system were calculated based on the Hyllerass-type trial wave function.According to the standard theory of Big Bang Nucleosynthesis (BBN), some of the lightest elements-hydrogen, helium, lithium and other few-body systems are the highest abundance in Cosmos. Because hydrogen and helium have the relatively simple structure of the atomic system, the research method of them is already mature in free-field. The calculation accuracy is very high. Previous methods are easy extended to the calculation of these simple systems in a strong magnetic field. These calculated data provide a detailed basis in astronomy.With the number of electrons increasing, however, calculation of the atomic systems is getting more and more difficult. The accuracy of the variational energy for low-lying states of lithium in free-field increases to14effective numerical in recent5years. Compared to the situation without magnetic fields, the accuracy of the variational energies for low-lying states of lithium is much worse in a magnetic, and the available data are rare. For that reason, the most accurate method to handle three-electron atomic systems in free-field was first extended to calculate the non-relativistic energies for three-electron atomic systems in a magnetic field. The main work of this dissertation is to improve the accuracy of the non-relativistic energies for three-electron atomic systems in a magnetic field. In the method, we solve the integeral formula for the arbitrary bound states of three-electron atomic systems in Hylleraas coordinates with magnetic, and give the basis for practice calculation, and then calculate the variational energies for low-lying states of three-electron atomic systems. Our calculation greatly improved the accuracy of the non-relativistic energies for three-electron atomic systems atom in a magnetic fields compared with the results obtained by other methods. Meanwhile some improved values for the dipole-oscillator strengths are obtained for lithium atom.