Spectroscopic and Collision Excitation Process for Li Atom Confined in a Gaussian Well With Application to Fullerene Confinement

Abstract

We report a detailed investigation of the spectral characteristics, electron-impact excitation dynamics, and de-excitation radiation processes of a lithium atom confined inside a $C_{60}$ fullerene cage. To this end, we propose a fully relativistic approach based on the Dirac-Coulomb Hamiltonian within a configuration-interaction framework. The confining effect of the cage is modeled using a power-exponential-model potential. Solutions of the modified Dirac equations provide both bound and continuum state wave functions. A feature of our approach is the replacement of the standard Coulomb interaction with a combined Coulomb potential and Breit interaction in the calculation of scattering matrix elements. As a representative application, we present detailed calculations of the Gaussian well with spherical confinement effects on the energy levels, transition probabilities, wave functions, total cross sections, magnetic cross sections, linear polarization of the radiation, and angular distribution of emitted photons for a Li atom inside $C_{60}$. Our predictions agree closely with other studies, demonstrating the reliability of the method and its potential usefulness in atomic physics, radiation physics, quantum chemistry, and materials science.