get_d4eeq_bj_parameter Subroutine

subroutine get_d4eeq_bj_parameter(dfnum, param, s9)
   integer(df_enum), intent(in) :: dfnum
   class(damping_param), allocatable, intent(out) :: param
   real(wp), intent(in), optional :: s9
   select case(dfnum)
   case(p_dftb_3ob)
      param = dftd_param( & ! (SAW191202)
         &  s6=1.0_wp, s8=0.4727337_wp, a1=0.5467502_wp, a2=4.4955068_wp)
   case(p_dftb_matsci)
      param = dftd_param( & ! (SAW191202)
         &  s6=1.0_wp, s8=2.7711819_wp, a1=0.4681712_wp, a2=5.2918629_wp)
   case(p_dftb_mio)
      param = dftd_param( & ! (SAW191202)
         &  s6=1.0_wp, s8=1.1948145_wp, a1=0.6074567_wp, a2=4.9336133_wp)
   case(p_dftb_ob2)
      param = dftd_param( & ! (SAW191202)
         &  s6=1.0_wp, s8=2.7611320_wp, a1=0.6037249_wp, a2=5.3900004_wp)
   case(p_dftb_pbc)
      param = dftd_param( & ! (SAW191202)
         &  s6=1.0_wp, s8=1.7303734_wp, a1=0.5546548_wp, a2=4.7973454_wp)
   end select

contains

   pure function dftd_param(s6, s8, a1, a2, alp) result(par)
      real(wp), intent(in) :: s8, a1, a2
      real(wp), intent(in), optional :: s6, alp
      type(rational_damping_param) :: par
      real(wp) :: s6_, alp_, s9_

      s6_ = 1.0_wp
      if (present(s6)) s6_ = s6
      s9_ = 0.0_wp
      if (present(s9)) s9_ = s9
      alp_ = 16.0_wp
      if (present(alp)) alp_ = alp

      par = rational_damping_param(&
         & s6=s6_, &
         & s8=s8, a1=a1, a2=a2, &
         & s9=s9_, &
         & alp=alp_)
   end function dftd_param

end subroutine get_d4eeq_bj_parameter