Theoretical Study On Properties Of Rydberg Atoms In The External Fields

One is interested in the study of Rydberg atoms because of its particular characteristics in external field. The behavior of Rydberg atoms in external field not only relates to many basic theoretical problems in atomic physics and quantum mechanics, and more importantly, it also relates to essential data for astrophysics, plasma physics, and other applications.In this thesis, with a kind of alkali-metal atomic potential model, the behaviors of the alkali-metal atom presented in the static electric field or microwave field are investigated using B-spline function as a basis function. The main works of this thesis are1. With a potential model of alkali-metal atoms and B-spline expansion technique, the anticrossings for the Stark energy level of Rubidium and Cesium atoms are investigated successfully. The stationary Schrodinger equation of Rubidium and Cesium atoms, which are presented in a static electric field, is solved numerically by diagonalization method. The structure and anticrossings of Stark energy levels for Rydberg Rubidium and Cesium atoms are calculated. The calculated positions and widths of the anticrossings are in agreement with the experimental data and other theoretical ones. According to our theoretical results, we have given some empirical formulas, by means of least-squares fits to our theoretical data, which can be used to estimate the positions of anticrossing for Rydberg states of Rubidium and Cesium in static electric field.2. The B-spline expansion technique and time-dependent two-level approach are applied to study the interaction between the microwave field and potassium atoms in a static electric field. Time-dependent Schrodinger equation of potassium atom in a static electric field and a microwave field is solved by close-coupling method. Themicrowave multiphoton transitions between the Stark states 19s→(17, 3) ofRydberg potassium atom are calculated. The multiphoton resonance spectrum obtained are in accord with the experimental measurement. Our results in the thesis show that using a potential model of alkali-metal atoms and B-spline expansion technique to investigate the characteristics of Rydberg atoms in external field is viable and effective. Compared with the traditional method, our method not only can give good results for the structure and anticrossings of Rydberg atoms in external field but also can save CPU time greatly.