write_pops_norm Subroutine

    subroutine write_pops_norm()

        use CalcData, only: pops_norm_unit

        if (iProcIndex /= root) return

        ! When calling for the first time, clear any current POPS_NORM file.
        if (pops_norm_unit == 0) then
            pops_norm_unit = get_free_unit()
            open (pops_norm_unit, file='POPS_NORM', status='replace')
        end if

        write (pops_norm_unit, '(1x,es19.12)') sqrt(pops_norm)

    end subroutine write_pops_norm