[CPMD-list] total energy variation

[Ari P Seitsonen]

Dear Luo,

   You should ALWAYS either first perform an optimisation of the electronic 
(or geometrical) structure, or at least use QUENCH BO. Now your initial 
state for the electrons is far away from Born-Oppenheimer surface and thus 
not very well (i.e. not at all) in equilibrium. Please do one of those 
first.

     Greetings from Lausanne,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   CNRS & IMPMC, Université Pierre et Marie Curie
   Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820

On Wed, 22 Nov 2006, Yi LUO wrote:

> Dear CPMD users
>
>  I performed a MD run for a charged cluster (isolated), MAXSTEP was set to
> be 2000  (please see following for the part of input file). It was found
> that the total enery varied in the large rang of 0.02 a.u. (~12 kcal/mol),
> even if it is run at 0 kelvin. The initial structure is a DFT-optimized
> minimum. This system is a non-metal system. the HTCH functional and the
> NORMCONSERVING pseudopotential was used.
>
>   Is there any improper parameters in my input ?
>
> Any comments on this matter would be very appreciated.
>
> Regards
> Luo
>
> ----------------------------
> &CPMD
>  MOLECULAR DYNAMICS
>  restart accumulators wavefunction coordinates velocities cell
>  restart nosec nosep nosee
>  restart latest
>  quench bo
>  ODIIS
>   5
>  MAXSTEP
>   2000
>  STORE
>   5000
>  TIMESTEP
>   3.0
>  EMASS
>   500.0
>  COMPRESS WRITE32
>  TRAJECTORY  XYZ
>  TEMPERATURE
>   0
> &END
>
> &DFT
>  FUNCTIONAL HCTH
>  GC-CUTOFF
>   1.0D-06
> &END
>
> &SYSTEM
>  CHARGE
>   1
>  SYMMETRY
>   0
>  CELL
>   15.000  1.0  1.0  0.0  0.0  0.0
>  CUTOFF
>   70.0
>  ANGSTROM
> &END
>
> &ATOMS
> ......
>
> ------------------------
>