[CPMD-list] md-run: crystal seems to explode

[Nico.Zobel at TU-Berlin.DE]

Dear Axel,

your hints were extremely helpful. Thank you very much!

I did two test-runs: 3000 timesteps of 2.0 a.u. at 300 K and 5000
timesteps at 800 K. In both cases the crystal seems to be stable.

As you suggested I changed

CONVERGENCE ORBITALS from 2.d-5 to 1.d-6,
CUTOFF from 60 to 30 Ry,
TESR from 4 to 1

and I added

GC-CUTOFF 5.d-6
DUAL 5.0
CHARGE -1.

The patches you provided have not been tested yet. That is going to happen
within the next few days (as soon as they are implemented at the HLRN).

But I have some further questions regarding your remarks:


AK> NZ>    84     Mg        .000000      11.692680      15.590239       3
AK> NZ>    85     Mg       7.795120      11.692680      15.590239       3
AK> NZ>  ****************************************************************
AK> NZ>
AK> NZ>  NUMBER OF STATES:                                            164
AK> NZ>  NUMBER OF ELECTRONS:                                   327.00000
AK> NZ>  CHARGE:                                                   .00000
AK>
AK> oooops. you have an odd number of electrons. i.e. you'll either need to
AK> adjust the charge of your system or run an 'open-shell' calculation by
AK> using the LSD keyword in the &CPMD section. note, that with LSD and PBE
AK> you'll need an update to your CPMD code. i'll attach a patch with
AK> the changes that will be in cpmd-v3.9.2, but it may not apply cleanly
AK> to the pristine cpmd-v3.9.1 sources (there were some overlapping
AK> other changes), YMMV.

As mentioned above, I could not test the patch so far. That is why I added
one electron by setting CHARGE to -1.
Do you think adding that electron leads to a significant change in the
chemical behaviour of my system? (I want to estimate activation energy by
blue-moon-ensemble method)
In other words:
If the patch does not apply cleanly (as you mentioned), can I still get
reasonable results by adding that electron?



AK> NZ>    ============================================================
AK> NZ>    |  pseudopotential report: version  7.3.5 date 10-15-2004  |
AK> NZ>    ------------------------------------------------------------
AK> NZ>    |  mg (Vol05)           PBE - GGA           exchange-corr  |
AK> NZ>    |  z =  12.00  zv =   2.00  exfact =   5.00000             |
AK> NZ>    |                            etot  =  -1.65416             |
AK> NZ>    |  index    orbital      occupation    energy              |
AK> NZ>    |    1        300           2.00        -.35               |
AK> NZ>    |  keyps = 3     ifpcor = 0                                |
AK> NZ>    |  rinner =      1.43     for L=    1                      |
AK> NZ>    |  rinner =      1.43     for L=    2                      |
AK> NZ>    |  rinner =      1.43     for L=    3                      |
AK> NZ>    |    new generation scheme:                                |
AK> NZ>    |    nbeta =  4     kkbeta =  583     rcloc =    3.1000    |
AK> NZ>    |    ibeta     l     epsilon   rcut iptype                 |
AK> NZ>    |       1      0        .00   3.00      0                  |
AK> NZ>    |       2      0       -.35   3.00      0                  |
AK> NZ>    |       3      1        .00   3.00      2                  |
AK> NZ>    |       4      1       -.35   3.00      2                  |
AK> NZ>    |  npf    = 6  ptryc =   8.000                             |
AK> NZ>    |  lloc   = 2  eloc   =    .000                            |
AK> NZ>    |  ifqopt = 3  nqf    = 6  qtryc =   8.000                 |
AK> NZ>    |  all electron calculation used koelling-harmon equation  |
AK> NZ>    |         ************logarithmic mesh************         |
AK> NZ>    ============================================================
AK>
AK> i am not 100% certain, that your mg-pseudo is compatible with cpmd.
AK> could you pleas apply the second attached patch to make the uspp
AK> reader reject incompatible potential files. this patch should also
AK> work for people still using v3.7.2, btw.

Again: This patch has not been tested, either.
My question is:
Which parameter(s) of the pseudopotential make you think that it might be
incompatible?
Maybe I can easily adjust the PP (i.e. the parameters in Vanderbilt's
code) to make it compatible ...

Thank you very much in advance -
Nico.

-- 
Dipl.Ing. Nico Zobel

Technische Universität Berlin  
Institut für Energietechnik  
Fachgebiet Energieverfahrenstechnik und  
Umwandlungstechniken regenerativer Energien (EVUR)

Fon:   +49 30 314 24381
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