Studies On Spectra Of Rydberg Sodium In Strong External Fields

Study on characteristics of Rydberg atoms in external fields have always been an important area of research in atomic physics, because it not only relates to many fundamental problems in atomic physics and quantum mechanics, but also provides the basic data for research in plasma physics, astrophysics and so on. On the experimental side, with the technology of the time of flight mass spectrometry combined with laser spectroscopy, a series of spectra of Rydberg sodium atoms in different external fields were measured. On the theoretical side, with the combination B-spline basis expansion and complex coordinate rotation, measured spectra were calculated. By comparing these two results carefully, a series of studies on core effect under different conditions have been carried out. Main work includes:(1)The effect of magnetic field on Rydberg sodium:We conducted experimental measurement of diamagnetic spectra for Rydberg sodium under various polarized laser excitation, also, the spectral line structure were well reproduced theoretically. In the case of π polarization, the theoretical results revealed anticrossing effect similar to the case of electric field and the significance of quantum defect channel np in determining the shape of diamagnetic spectra. For the situation of the σ or complex polarization, by decomposing on three basic polarization schemes of the σ+, σ- and π, the experimental results were well reproduced and no coupling between excited states with these three basic polarization schemes are observed.(2) The effect of electric field on Rydberg sodium:Stark spectra of Rydberg sodium atoms in the excitation with π and σ polarized laser were experimentally measured, the anticrossing effect of π polarized spectra was indicated in the form of Stark map, which clearly showed the non-hydrogenic core effect. Then, we also studied the Stark effect of the structure of the diamagnetic spectra, and observed the spectral line splitting and the redistribution of the spectral intensities, and also confirmed the evolution trend of the three types states.(3) The visualization of core effect of non-hydrogenic atoms in the electric field: The oscillator strength and electronic probability distribution of three kinds of systems were calculated with the exact quantum defect theory. We showed that the core effect can be clearly visualized in the form of electron probability distribution and the irregular oscillator strength distribution can be explained in the perspective of approximate symmetry of wavefunction near the core. Theoretical calculation results are strongly supported by experimental data.