Recurrence Spectra Of Li Atom In Parallel Electric And Magnetic Fields, The Semi-classical Study

The success of the semiclassical closed-orbit theory lie in its clear physical picture and wide application sphere, so it can be used widely to explain photoabsorption of atom or ion in external fields. This theory has provided the strong tool for studying the classical correspondences of quantum spectra; and has gained the very big success for the quantum manifestations of classical chaos. No matter for integrable system associated with regular motion or the unintegrable system in irregular motion, and all can be given a clear physical explanation. The theory has got the extensive application in descripting the photoabsorption of H - in the various external fields , as well as the high excited states of hydrogen atom, Li atom, He atom and 03 etc in electric field or magnetic field,and Rydberg wave packet dynamics. Through the experimental and theoretical researches of the nonhydrogenic atoms in strong external feud, it is found that in the recurrence spectra of nonhydrogenic atoms there exist the new strong resonance structure, which can not be explained by the orbits of hydrogen atom , and it is neccesary to take the effects of the ionic core into account in case of the nonhydrogenic atoms,and the scattering peaks originated from ionic core should contribute to their recurrence spectra. When this 3 Abstract semiclassical closed-orbits theory is extended to nonhydrogenic atoms, the number of closed-orbits increase rapidly due to the effect of core-scattering, and most of those are unstable and are not easily classified , that make the problem more complicated. In this thesis, we have used region-splitting consistent and iterative method together with the quantum core-scattering that is by using of the quantum defects to show the core effects, and core- scattering orbits are all combinated by closed-orbits of hydrogen atom. Thus, having surmount these difficulties, semiclassical closed-orbit theory can be applied to Li atom in parallel electric and magnetic fields. Employing the semiclassical closed-orbit theory including quantum core-scattering, we calculated the recurrence spectra of Li atom in parallel electric and magnetic fields for two different scaled energy and compared it with the corresponding hydrogenic system, arrived at the expected results; we also carried out a scaling transformations, and checked the convergency. Our efforts are as follows: (1) We analysised the classical motion in two different scaled energy (s = 0.58 ands = 0.OO6at fixed scaled electric fields strengthf 0.036), obtained the number of closed-orbits, the outgoing angles, and the returning times. (2) In the semiclassical closed-orbit theory framework, we calculated the Jacobian and semiclassical amplitude and classical action as well as the Maslov index. We got the semiclassical wave function thus. (3) Based on the extending semiclassical approach, we made the scaling transformation and calculate the iterative solutions. (4) Via Fourier trasformation, the photoabsorption spectra can be written as the function of scaled classical action from the function of energy. Then, 4 Abstract we obtained the recurrence...