  We formulate the blended force-based quasicontinuum (BQCF) method for
multilattices and develop rigorous error estimates in terms of the
approximation parameters: atomistic region, blending region and continuum
finite element mesh. Balancing the approximation parameters yields a convergent
atomistic/continuum multiscale method for multilattices with point defects,
including a rigorous convergence rate in terms of the computational cost. The
analysis is illustrated with numerical results for a Stone--Wales defect in
graphene.
