Inequivalent solutions for Dirac spin-1/2 particles under conservation of parity II

By law of conservation of parity we show that Dirac equation in an electromagnetic field can be split up into two uncoupled two-component equations. As a result, we shall find twice as many as the conventional solutions. For free particles four linearly independent plane wave solutions which hold for E > 0 and also for E < 0 can be established. In a Coulomb field we shall easily find the stationary solutions. (C) 2011 American Institute of Physics. [doi:10.1063/1.3578753]