[Pw_forum] minimization in CP molecular dynamics

[Mansoureh Pashangpour]

dear Nicola
this is ekinc for end of minimization I found it small after verlet dynamics
 ekinc         :        0.10064       0.10064 (AU)
 ekin          :      144.72166     144.72166 (AU)
   epot          :     -473.07863    -473.07863 (AU)
   totel energy  :     -280.01088    -280.01088 (AU)

why they are different with
> scf:  total energy              =  -243.33284101 Ry
Thanks

On Thu, Jul 10, 2008 at 11:50 AM, Nicola Marzari <marzari at mit.edu> wrote:

>
>
> Shouldn't ekinc be zero ? I forgot the name used, but in a properly
> executed CP calculation, in which you do damped dynamics on the
> electrons to reach the ground state at fixed ions, the kinetic energy
> of the electrons (as opposed to the quantum kinetic energy of your
> system, ekin) should be zero.
>
> I suggest to anyone learning CP calculations (a very worthy
> endeavour, and one that would be extremely useful in the long
> run) to study carefully the review paper on the topic by Marx and
> Hutter,
>
> http://www.theochem.ruhr-uni-bochum.de/research/marx/marx.pdf
>
> CP in Q-E now can also do conjugate gradients minimization on
> the electrons (more efficient than damped dynamics) and, for
> metals, ensemble-dft (i.e. born-oppenheimer dynamics).
>
> For cg/edft, there was one bug (memmory misallocation)
> for parallel execution, just found by by Brandon Wood. It'll
> be fixed in the cvs in the next few days.
>
>
>                        nicola
>
> Mansoureh Pashangpour wrote:
> > Dear Paolo
> > I know one of them is in Ry and another one in Ha,but when I compare
> > them they are different
> > scf:  total energy              =  -243.33284101 Ry
> >
> > CP:  ekinc         :       10.67409      10.67409 (AU)
> >    ekin          :      153.58930     153.58930 (AU)
> >    epot          :     -458.58466    -458.58466 (AU)
> >    totel energy  :     -258.18270    -258.18270 (AU)
> >    temperature   :        0.00000       0.00000 (K )
> >    enthalpy      :     -258.18270    -258.18270 (AU)
> >    econs         :     -258.18270    -258.18270 (AU)
> >    pressure      :       -3.47982      -3.47982 (Gpa)
> >    volume        :      488.11442     488.11442 (AU)
> > Thanks
>
> --
> ---------------------------------------------------------------------
> Prof Nicola Marzari   Department of Materials Science and Engineering
> 13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
> tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
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