Calculation of Higher-Order Foldy-Wouthuysen Transformation Hamiltonian
MEI Xue-Song1, ZHAO Shu-Min2,3, QIAO Hao-Xue1**
1School of Physics and Technology, Wuhan University, Wuhan 430072 2College of Physics and Technology, Hebei University, Baoding 071000 3Division of Theoretical and Interdisciplinary Research, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071
The Foldy–Wouthuysen Hamiltonian of a light atomic system that has an mα8 contribution to energy levels is calculated. The case of a Dirac–Coulomb field is discussed. The results can be used for relativistic and radiative corrections to energy levels in the low-energy part. A divergent operator δ2(r) emerges. This is probably due to the nature of the point-like charge source. The effective method of radiation calculation may be re-checked.