Reduction of ionic liquid anion on Na surface

[sreehari B R]

Hello everyone,

I am studying the reduction mechanism of my anion on a Na surface using CP2K. However, I am encountering an issue where no reduction occurs on the Na surface, while the same setup shows anion reduction on a Li surface. The CP2K simulation does not produce any errors, making it challenging to diagnose the problem.

My workflow involves:

1. Minimization using LAMMPS
2. Geometry optimization
3. AIMD (Ab Initio Molecular Dynamics)

I have attached my AIMD script for reference. Could someone please help me identify what might be causing the lack of anion reduction on the Na surface? Any insights or suggestions would be greatly appreciated.

Thank you in advance for your assistance!
AIMD input file:
&GLOBAL
  PROJECT 100_IL
  RUN_TYPE MD
  IOLEVEL LOW
&END GLOBAL

&FORCE_EVAL
  METHOD QS
  &DFT
    BASIS_SET_FILE_NAME ./BASIS_MOLOPT
    POTENTIAL_FILE_NAME ./GTH_POTENTIALS
    CHARGE 0
    LSD
    &QS
      EPS_DEFAULT 1.0E-10
    &END QS
    &MGRID
      CUTOFF 600
      NGRIDS 4
      REL_CUTOFF 60
    &END MGRID
    &SCF                              
      SCF_GUESS ATOMIC
      MAX_SCF 200
      EPS_SCF 1.0E-4
      &OT
        PRECONDITIONER FULL_SINGLE_INVERSE
        MINIMIZER DIIS
      &END OT
      &OUTER_SCF
        MAX_SCF 200
        EPS_SCF 1.0E-4
      &END OUTER_SCF
      &PRINT
        &RESTART OFF
        &END
      &END PRINT
    &END SCF
    &XC
      &XC_FUNCTIONAL PBE
      &END XC_FUNCTIONAL
      &VDW_POTENTIAL
        POTENTIAL_TYPE PAIR_POTENTIAL
        &PAIR_POTENTIAL
          PARAMETER_FILE_NAME dftd3.dat
          TYPE DFTD3
          REFERENCE_FUNCTIONAL PBE
          R_CUTOFF [angstrom] 16
        &END PAIR_POTENTIAL
      &END VDW_POTENTIAL
    &END XC
  &END DFT

  &SUBSYS
    &CELL
      ABC [angstrom] 12.5000 12.5000 30.000
    &END CELL
    &TOPOLOGY
      COORD_FILE_NAME EM_TFSI-pos-1.xyz
      COORD_FILE_FORMAT XYZ
    &END TOPOLOGY

    &KIND H
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q1
    &END KIND
    &KIND F
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q7
    &END KIND
    &KIND O
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND C
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND S
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND N
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q5
    &END KIND
    &KIND Si
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND Na
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q9
    &END KIND
  &END SUBSYS
&END FORCE_EVAL

&MOTION
  &GEO_OPT
    OPTIMIZER LBFGS
    MAX_ITER 100
    MAX_DR [bohr] 0.003
    &BFGS
    &END BFGS
  &END GEO_OPT

  &MD
    ENSEMBLE NVT
    TEMPERATURE [K] 350
    TIMESTEP [fs] 1
    STEPS 30000
    &THERMOSTAT
      TYPE NOSE
      &NOSE
        TIMECON 50
      &END NOSE
    &END THERMOSTAT
  &END MD

  &PRINT
    &TRAJECTORY
      &EACH
        MD 1
      &END EACH
    &END TRAJECTORY
    &VELOCITIES OFF
    &END VELOCITIES
    &FORCES OFF
    &END FORCES
    &RESTART_HISTORY
      &EACH
        MD 5000
      &END EACH
    &END RESTART_HISTORY
    &RESTART
      BACKUP_COPIES 2
      &EACH
        MD 1
      &END EACH
    &END RESTART
  &END PRINT

  &CONSTRAINT
    &FIXED_ATOMS
      COMPONENTS_TO_FIX XYZ
      LIST 1 19 37 7 25 43 13 31 49 2 20 38 8 26 44 14 32 50 3 21 39 9 27 45 15 33 51
    &END FIXED_ATOMS
  &END CONSTRAINT
&END MOTION

Regards,

Sreehari