Imaginary Time Step Method to Solve the Dirac Equation with Nonlocal Potential

The imaginary time step (ITS) method is applied to solve the Dirac equation with nonlocal potentials in coordinate space. Taking the nucleus $12C$ as an example, even with nonlocal potentials, the direct ITS evolution for the Dirac equation still meets the disaster of the Dirac sea. However, following the recipe in our former investigation, the disaster can be avoided by the ITS evolution for the corresponding Schrödinger‐like equation without localization, which gives the convergent results exactly the same with those obtained iteratively by the shooting method with localized effective potentials.