The Thomas Precession Factor in Spin-Orbit Interaction
arXiv:physics/0310016 · doi:10.1119/1.1615526
Abstract
The origin of the Thomas factor 1/2 in the spin-orbit hamiltonian can be understood by considering the case of a classical electron moving in crossed electric and magnetic fields chosen such that the electric Coulomb force is balanced by the magnetic Lorentz force.
PDF File, 5 pages, to appear in American Journal of Physics