[CPMD-list] Why convergence is so slow?

[Yang Zhenyu]

 Dear CPMD users:

      I try to calcluate a molecule adsorption on Ni surface with GH-pseudopotentials, but I find it is very hard to converge in the geometry optimization. So I post my input here, hoping anybody can give me some advices!

-------------------------------
&CPMD
    OPTIMIZE GEOMETRY
    TRAJECTORY XYZ
    UNIT HESSIAN
    BFGS
    FREE ENERGY FUNCTIONAL
    LANCZOS DIAGONALISATION 
    LANCZOS PARAMETERS
      1   6 10   1.D-18
    TROTTER FACTOR
      0.001
    BOGOLIUBOV CORRECTION OFF 
    GRAM-SCHMIDT ORTHOGONALISATION
    CONVERGENCE
      1.D-4  5.D-4
    MAXSTEP
      500
    BROYDEN MIXING
      0.3 200   0.01  0   8
    ALEXANDER MIXING
      1.1
    ELECTRON TEMPERATURE
      1000.
    COMPRESS WRITE32
    STRUCTURE BONDS
    RHOOUT
    WANNIER WFNOUT ALL
    PRINT ON
&END

&SYSTEM
 POINT GROUP
 AUTO
 SYMMETRY
  4
 ANGSTROM
 CELL
 7.3818     1.0     5.0       0.00       0.00       -0.5
 CHARGE
 0 
 CUTOFF
 60
 TESR
 3
&END

&DFT
 NEWCODE
 FUNCTIONAL PBE
&END

&ATOMS
*Ni-q18-pbe KLEINMAN-BYLANDER                                           
 LMAX=P
..................................... 

*N-q5-pbe KLEINMAN-BYLANDER              
 LMAX=P
.....................................
 
*C-q4-pbe KLEINMAN-BYLANDER            
 LMAX=P
.....................................
 
*H-q1-pbe KLEINMAN-BYLANDER             
..................................... 
   CONSTRAINTS
   FIX ATOMS
    8
    1  2  3  4  5  6  7  8
  END CONSTRAINTS
&END

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¡¡¡¡¡¡¡¡¡¡¡¡¡¡
¡¡Best Regards

¡¡Yang Zhenyu				
  State Key Laboratory of Nonlinear Mechanics (LNM)
  Institute of Mechanics, Chinese Academy of Sciences
  No.15 Beisihuanxi Road
  Beijing 100080, P. R. China
  FAX: 010-62579511
¡¡yangzy at lnm.imech.ac.cn
¡¡2005-12-02