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["Jin Zhang" <jin.zhang.pku@gmail.com>]

Hi,

 

I think your calculation may be not converged w.r.t. acell and ecut.
What kind of psps did you use? 12Ha for carbon is two low if you used ncpp. Raise it to 30-40Ha if you want meaningful result. Another issue, are you sure 10Bohr is large enough to avoid interaction between the molecule and its periodic images?

 

Best,
JZ

On 8/24/07, farah marsusi <fmarsusi@yahoo.com> wrote:

Dear Fabien
1-I have done all correction you and others advised.The result was too better( a little more than 2 ev instead of 3 Hartree)but still it is far from experiment 1.1ev.1-Is any other suggestion ?Here is my in put file.

 

2-Besides I tried to perform gw calculation ,but unfortunately most of tutorial examples provided for crystaline structure not for molecules .The out put file stops in seconed data set ,I dont know why?

thank you

Farah
 

ndtset 2   #  TWO KINDS OF PARTICL :NEUTRAL AND NEGATIVE CHARGED
acell 10 10  10
ecut 12
ionmov1 3
ionmov2  0
ntypat 2
natom 2
typat 1 2
znucl 6 1
ixc  11
occopt  2 
# -----------------------------

nband  5  5
nsppol  2
occ1 1 1 1 0 0  1 1 0 0 0
occ2   1 1 1 0 0 1 1 1 0 0
# -----------------------------
charge2  -1
charge1 0
#-----------------------------------
xangst
          0.000000    0.000000    0.158311
          0.000000    0.000000   -0.949865

getxcart -1
#-------------------------------------
nkpt  1
diemac 1
#-----------------------------------
toldfe  5.0d-8
ntime1  20
ntime2  30
nstep 20

 

 

 

 

 

 

 

 

 

 

Fabien Bruneval <fabien.bruneval@polytechnique.fr> wrote:

Dear Farah,

I just want to say in addition to all previous comments that the
electron affinity is defined as the difference between the neutral and
the charged molecule with the SAME geometry (of the neutral molecule).
Indeed, the time scale needed to inject an additional electron in the
system is much much shorter than the time scale of the atomic relaxation.
Let us know the final result with correct occupancies, correct geometry
and spin-polarization...


Fabien




Jin Zhang wrote:
> Dear Farah,
>
> Would you mind giving it a try to perform a spin-ploarized calculation?
>
> Best,
> Jin Zhang
>

> On 8/18/07, *farah marsusi* > > wrote:
>
> Dear users:
> In order to compute affinity of CH, I made an in put file for
> computing total energy of neutral and negative charged CH and then
> subtract them : E(CH)-E(CH)^- ,but the result is not correct(
> about 3ev) and differs from experiment(1.1 ev) .Is there any one
> tell me what is my mistake?
> Here is my in put file for CH ^- and CH after convergence test :
>
> ndtset 2
> acell 10 10 10
> ecut 12
> ionmov 2
> ntypat 2
> natom 2
> xangst
> 0.000000 0.000000 0.158311
> 0.000000 0.000000 -0.949865
> ixc 11
>
> charge1 0 # neutral particle
> nband1 5
> occ1 2 2 1 0 0
>
> charge2 -1 # charged particle
> nband2 5
> occ2 2 2 1 1 0
>
> typat 1 2
> znucl 6 1
> nkpt 1
> toldfe 5.0d-8
>
>
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> --
> MPhil
> Dept. of Physics, Peking University
> Beijing, 100871, P.R.China
> Phone: 86-10-62768590

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MPhil
Dept. of Physics, Peking University
Beijing, 100871, P.R.China
Phone: 86-10-62768590