QEDMOD: Fortran program for calculating the model Lamb-shift operator

We present Fortran package QEDMOD for computing the model QED operator h^QED that can be used to account for the Lamb shift in accurate atomic-structure calculations. The package routines calculate the matrix elements of h^QED with the user-specified one-electron wave functions. The operator can be used to calculate Lamb shift in many-electron atomic systems with a typical accuracy of few percent, either by evaluating the matrix element of h^QED with the many-electron wave function, or by adding h^QED to the Dirac–Coulomb–Breit Hamiltonian.