Investigation On The Energy Levels And The Fine Structure Of Beryllium-like Atoms

In this thesis, based on Racah theory and non-relativistic energy structure for Beryllium-like atoms, the relativistic corrections and the fine structure of Beryllium-like atoms, including the relativistic mass correction, the Darwin correction terms, the electron-electron contact terms, the orbit-orbit interaction, the spin-orbit interaction, and the spin-other-orbit interaction , are studied systematically using irreducible tensor theory. Analytical method for calculating the relevant angular integration and spin summation is established. There are four chapters in this paper. The main contents are listed as following:In chapter one, the theory of the angular momentum operator and the basic principle of the angular momentum coupling are briefly introduced. In chapter two, with the help of angular momentum coupling theory, the Hamiltonian for multi-electron atoms is rewritten in form of spherical tensors operators. The advantage of this form is that the radial, angular and spin parts are separated completely, which makes it easy to calculate the angular matrix elements by means of irreducible tensor.In chapter three, by using irreducible tensor theory, the method for calculating the relativistic corrections to 1s 22s21S,1s 2 2s2p3P and 1s 2 2s2p1P states of Beryllium-like atoms is presented, in which the...