d4_calculation Subroutine

subroutine d4_calculation(io, env, options, mol_, param_, res)
   integer, intent(in) :: io
   type(mctc_logger), intent(inout) :: env
   type(dftd_options), intent(in) :: options
   type(molecule), intent(in) :: mol_
   type(dftd_parameter), intent(in) :: param_
   type(dftd_results), intent(out) :: res

   type(structure_type) :: mol
   type(d4_model) :: d4
   type(rational_damping_param) :: param
   real(wp), allocatable :: energy, gradient(:, :), sigma(:, :)

   call new(mol, mol_%at, mol_%xyz, lattice=mol_%lattice)
   call new_d4_model(d4, mol, ga=options%g_a, gc=options%g_c, wf=options%wf)
   param = rational_damping_param(&
      & s6=param_%s6, &
      & s8=param_%s8, &
      & s9=param_%s9, &
      & a1=param_%a1, &
      & a2=param_%a2, &
      & alp=param_%alp)

   allocate(energy, gradient(3, mol%nat), sigma(3, 3))
   call get_dispersion(mol, d4, param, realspace_cutoff(), energy, gradient, sigma)
   call move_alloc(energy, res%energy)
   call move_alloc(gradient, res%gradient)
   res%lattice_gradient = matmul(sigma, transpose(matinv_3x3(mol%lattice)))

end subroutine d4_calculation