[CP2K-user] Convergence problem- MD calculation for metal surface

Amin amin.ja... at gmail.com
Sun Mar 31 22:27:50 UTC 2019

Dear all,
I'm encountering convergence problem for the MD simulation of single 
molecule adsorption on Ni surface. This is a test case to see if I can 
calculate my desired system. I'm using a GLE thermostat. 
I've tried using DFTB and PM6 but in both cases I receive the error below, 
*"Bad condition number R_COND = 0.000E+00 (smaller than the machine working 
precision"  common/mathlib.F:709.*
As you know, DFTB or PM6 are chosen because of their inexpensiveness! 

[image: Capture.PNG]

Here is my input file and I've attached the coordinate file:

        PROJECT CH4-Ni
        RUN_TYPE MD

        METHOD Quickstep
      METHOD PM6
       RC_INTERACTION [angstrom] 8.0
       RC_COULOMB     [angstrom] 8.0
       RC_RANGE       [angstrom] 0.05
    &END QS
   ! &QS
   !   &DFTB
   !     DO_EWALD           T
   !     DISPERSION         T
   !     &PARAMETER
   !       PARAM_FILE_PATH  /data/scc
   !       PARAM_FILE_NAME  scc_parameter
   !       UFF_FORCE_FIELD  uff_table
   !   &END DFTB
   ! &END QS
                        MAX_SCF 30
                        EPS_SCF 5.0E-6
                                MAX_SCF 30
                                EPS_SCF 5.0E-6
                        &DIAGONALIZATION  ON
                                ALGORITHM STANDARD
                        &END DIAGONALIZATION
                        ADDED_MOS 300
                        &SMEAR  ON
                                METHOD FERMI_DIRAC
                                ELECTRONIC_TEMPERATURE [K] 350
                        &END SMEAR
                                METHOD BROYDEN_MIXING
                                BETA 1.5
                                ALPHA   0.1
                                NBROYDEN  8
                        &END MIXING
                                &RESTART LOW
                                        BACKUP_COPIES 1
                                &END RESTART
                        &END PRINT
                        SCF_GUESS ATOMIC
                &END SCF    
                        POISSON_SOLVER MT
                        PERIODIC XY
       GMAX 25
       O_SPLINE 5
      &END EWALD
                &END POISSON
        &END DFT

                        ABC 12.4597 12.9485 23.1387
                        PERIODIC XY
                &END CELL
@INCLUDE 'ch4-ni.coord'
        &END COORD

                ENSEMBLE NVT
                STEPS 10000
                TIMESTEP 0.5
                TEMPERATURE 300
                        REGION MASSIVE
                        TYPE GLE
                                NDIM 3
                                A_SCALE [ps^-1] 1.00
                                A_LIST    2.000000000000e+0   
1.365763041717e+1   0.000000000000e+0
                                A_LIST   -1.365763041717e+1   
9.418257899376e-1   5.860040064992e+2
                                A_LIST    0.000000000000e+0  
-5.860040064992e+2   0.000000000000e+0
                                C_LIST    3.071856358605e+2   
1.052252204958e+0  -3.083120039764e+2
                                C_LIST    1.052252204958e+0   
1.353606645969e+4   0.000000000000e+0
                                C_LIST   -3.083120039764e+2   
0.000000000000e+0   1.352888082383e+4
                        &END GLE
                &END THERMOSTAT
                                        MD 10
                                &END EACH
                        &END ENERGY
                &END PRINT
        &END MD
                                MD 1000
                                        COMMON_ITERATION_LEVELS 3
                                                MD 1
                                        COMMON_ITERATION_LEVELS 3
                                                MD 1
                &END METADYN
                        FORMAT XYZ
                                MD 20
                        &END EACH
                &END TRAJECTORY
                                MD 10000
                        &END EACH
                &END RESTART_HISTORY
                &RESTART OFF
                &END RESTART
        &END PRINT

I would be grateful if anyone could take a look to my input file and let me 
know about the possible way to get the structure converged. I've already 
relaxed the metal structure before using it for md simulation. 
Thanks in advance.

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