&GLOBAL
  PROJECT 2d_polymer
  RUN_TYPE ENERGY
&END GLOBAL

&FORCE_EVAL
  &DFT
    &LS_SCF
      EPS_FILTER 1E-5  ! threshold used to determine sparsity
      MU         -0.15 ! chemical potential, an energy from within in the HOMO-LUMO gap
    &END

    &QS
      LS_SCF  ! Turns on linear scaling DFT. Comment this line to run with normal SCF.

! =============================================================================================
! === Description of Hamiltonian (Density Functional Tight Binding + Particle Meshed Ewald) ===
      METHOD DFTB
      &DFTB
        HB_SR_GAMMA 
        SELF_CONSISTENT    T
        DO_EWALD           T
        DISPERSION         T
        &PARAMETER
          PARAM_FILE_PATH  ./dftb_params/scc
          PARAM_FILE_NAME  scc_parameter
          UFF_FORCE_FIELD  uff_table
        &END PARAMETER
      &END DFTB
    &END QS
    &POISSON
      &EWALD
       EWALD_TYPE SPME
       GMAX 160
       O_SPLINE 5
      &END EWALD
    &END POISSON
! ==============================End of Hamiltonian Description ================================
! =============================================================================================
  &END DFT

! Number of unit cell replications, increase this to create a large polymer.
@SET NREP 1
  
  &SUBSYS
    &CELL
      ABC 23.577999 40.8383 30
      MULTIPLE_UNIT_CELL 1 ${NREP} 1
    &END CELL
    &TOPOLOGY
      MULTIPLE_UNIT_CELL 1 ${NREP} 1
    &END
    &COORD
@INCLUDE '2d_polymer.coord' 
    &END COORD
  &END SUBSYS
&END FORCE_EVAL