R. Arvieu et al., Spin dynamics of wave packets evolving with the Dirac Hamiltonian in atomswith high atomic number Z - art. no. 022514, PHYS REV A, 6202(2), 2000, pp. 2514
The motion of circular wave packets for one electron in a central Coulomb f
ield with a high atomic number Z is calculated. The wave packet is defined
in terms of solutions of the Dirac equation in order to take into account a
ll possible relevant effects, in particular the spin-orbit potential. A tim
e scale is defined within which spin dynamics must be taken into account, m
ainly in atoms with high Z. Within this time scale there exists a mechanism
of collapses and revivals of the spin, already shown by the authors for ha
rmonic oscillator potential and called the spin-orbit pendulum. Though this
effect does not have the exact periodicity of the simpler model, the wave
packet spatial motion is nevertheless quite similar.