Recurrence Spectra Of The Rydberg Helium Molecule Ion In External Fields

Comparing to a lot of the experimental spectra and theoretical calculation results, the photoabsorption spectra of the Rydberg molecules in strong external field have attracted little attention. Until recently we have all discussed the single channel scattering process. Whereas as for a typical Rydberg elctron, when placed in external field, multi-channel scattering phenomena will appear, during the collision of the Rydberg electron with the nuclear, their quantum state will be altered. Even for the simple molecule, this phenomenon existed and must be treated by using the multi-channel quantum defect theory.In order to simulate the scattering influence of the molecular core, we put forward a new potential. The main content of this dissertation is to calculate therecurrence spectra of the Rydberg helium molecule ion (He₂⁺ ) in parallel electric andmagnetic fields by using the semiclassical closed orbit theory and the new potential. The main works are as the following chapter:In chapter 1, which is a brief introduction of the establishment and the development of the molecular closed orbit theory collectively, the subject we choose and the main work we have done.In chapter 2, In order to simulate the scattering influence of the molecular core( He₂⁺ ) , we use the theory of molecular orbits to obtain the analytic expression ofthe potential of the excited electron in Rydberg helium molecule ion (He₂⁺). Wealso give some potential diagrams so as to understand the role of every part of the potential.In chapter 3, After adopting the Thiele-Burrau's transformation to the Hamiltonion , we solve the Hamilton motion equation and then find the closed orbits of helium molecule ion. And we classify those orbits according to the molecular closed orbits theorem.In chapter 4, we calculate the recurrence spectra of the Rydberg helium molecule in parallel electric and magnetic fields, using the multi-channel quantum defect theory...