Theoretical Study On Electronic Structures Of Ca~+-X(X=He,Ca~+) Systems

In the high-precision quantum frequency standard,many technologies will be used to restrain the broadening factors of atomic spectra.The interaction between the particles has become one of the significant broadening factors.⁴⁰Ca⁺ion is widely used in the research of quantum computation and quantum frequency standard.We focus on the research of electronic structures and transitional properties of Ca⁺-He system and Ca⁺-Ca⁺system.And as a type of background gas atoms,how He atoms affect the broadening and shifting of the spectra of Ca⁺.In this dissertation,the electronic structures and transitional properties of Ca⁺-He system and Ca⁺-Ca⁺system are carefully calculated and analyzed.Our work includes:The potential energy curves associated with three lowest dissociation limits of Ca⁺-He system are calculated using MRCI method,where the Davidson correction is taken into account in the calculations.These results are in accordance with the experimental results.And we also calculated the transition dipole moments and transition quadrupole moments including ground state X²?⁺_1/2,which are varied with the internuclear separation R,to investigate the transitional properties.?2?With the Anderson-Talman theory,we obtain the broadening and shifting coefficients of H line and K line of Ca⁺-He system based on the calculated potential energy curves.?3?The electronic structures associated with three lowest dissociation limits of Ca⁺-Ca⁺system are calculated using MRCI method,where the spin-orbital coupling is taken into account in the calculations.We obtain the spectroscopy constants,vertical transition energy and oscillator strength using LEVEL program.