[CPMD-list] problem designing SiO2 slab

[Abraham Alaka]

 --- Younes Ansari <ara_1357_2416 at yahoo.com> wrote: 
> dear sir:
>     I have designed a slab of quartz and I want to
> know if there isn`t any  problem with it.
When you say slab, Im guessing (perhaps wrongly) the
"mirror images" are only meant to be in the x and y
directions. If this is the case you will finad it a
lot easier using the SLAB keyword in the &SYSTEM
section.

There are one or two things to look out for when using
this keyword so you might find it helpful to consult
the online manual at cpmd.org, particularly the notes
at the bottom.

If you are going o use the SLAB keyword, you might
find it easier to take some atoms out of the
simulation cell since increasing the volume may mean
you are running out of memory (Im guessing thats what
you meant above).

>     The SiO2 volume is 290 A' so it wont be any
> problems to have 
> CELL
>     10.000   1.0   1.0  0  0.0  
> Because if I chage it to 11.00 or more the program
> wont be run . 
>  
> I have an other problem beacause my programs do not
> mach with the tutorial that Dr. Kohlmayer have made.
> for example..
>  
> WAVEFUNCTION
>  
> &CPMD
>     OPTIMIZE WAVEFUNCTION
>     INITIALIZE WAVEFUNCTION
>     .
>     .
>   if i dont use the INITIALIZE WAVEFUNTION in CPMD
> 3-9-1 my program wont run even in GEOMETRY
> OPTIMIZATION and MOLECULAR DYNAMICS CP. So is there
> a problem with the input files.
> NOTE: The tutorial of theochem wont be run unless I
> chage it to INITIALIZE WAVEFUNCTION.
The INITIALIZE WAVEFUNCTION keyword (I think) is used
to tell cpmd what to assume the initial wavefunction
of your system is like (i.e I normally set it to
INITIALIZE WAVEFUNCTION RANDOM). I've looked at your
input and I dont get why it doesn't run without
"INITIALIZE WAVEFUNCTION". You might want to check how
you've specified the dimensions of the simulation cell
or even the coordinates of the atoms within the cell.

The CUTOFF might also need increasing once you get it
running.

Since this refers to the tutorial, others can probably
shed a lot more light than I've been able to.

Hope this helps, Good luck.

A.  
>   
> 
> 
> 		
> ---------------------------------
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&CPMD
>   MOLECULAR DYNAMICS CP
>   INITIALIZE WAVEFUNCTION
>   TRAJECTORY XYZ
>   MAXSTEP
>     12
> &END
> 
> &SYSTEM
>   SYMMETRY
>     1
>   CELL
>     10.000  1.0  1.0  0  0  0
>   CUTOFF
>     70.0
>   ANGSTROM
> &END
> 
> &ATOMS
> *Si_SG_LDA  KLEINMAN-BYLANDER
>    LMAX LOC
>    12
>    	-2.526	1.45838678	0.51274
>   	-2.526	-1.45838678	4.64774
>   	-2.526	1.45838678	3.62226
>   	-2.526	-1.45838678	7.75726
>   	0.000	2.91677356	4.64774
>   	0.000	2.91677356	7.75726
>   	0.000	-2.91677356	0.51274
>   	0.000	-2.91677356	3.62226
>   	2.526	1.45838678	0.51274
>   	2.526	-1.45838678	4.64774
>   	2.526	1.45838678	3.62226
>   	2.526	-1.45838678	7.75726
> 
> 
> *O_SG_LDA  KLEINMAN-BYLANDER
>    LMAX
>    42
> 	-2.526	1.45838678	2.0675
> 	-2.526	-1.45838678	6.2025
> 	-3.789	-2.18758017	0
> 	-3.789	2.18758017	0
> 	-2.526	0	 	0
> 	-3.789	-2.18758017	4.135
> 	-3.789	2.18758017	4.135
> 	-2.526	0		4.135
> 	-3.789	-2.18758017	8.27
> 	-3.789	2.18758017	8.27
> 	-2.526	0		8.27
> 	0	2.91677356	6.205
> 	-1.263	2.18758017	0
> 	0	4.37516034	0
> 	-1.263	2.18758017	4.135
> 	0	4.37516034	4.135
> 	-1.263	2.18758017	8.27
> 	0	4.37516034	8.27
> 	0	-2.91677356	2.0675
> 	-1.263	-2.18758017	0
> 	0	-4.37516034	0
> 	-1.263	-2.18758017	4.135
> 	0	-4.37516034	4.135
> 	-1.263	-2.18758017	8.27
> 	0	-4.37516034	8.27
> 	2.526	1.45838678	2.0675
> 	2.526	-1.45838678	6.2025
> 	1.263	-2.18758017	0
> 	1.263	2.18758017	0
> 	2.526	0		0
> 	1.263	-2.18758017	4.135
> 	1.263	2.18758017	4.135
> 	2.526	0		4.135
> 	1.263	-2.18758017	8.27
> 	1.263	2.18758017	8.27
> 	2.526	0		8.27
> 	3.789	2.18758017	0
> 	3.789	2.18758017	4.135
> 	3.789	2.18758017	8.27
> 	3.789	-2.18758017	0
> 	3.789	-2.18758017	4.135
> 	3.789	-2.18758017	8.27
> 
> &END
> 		
> &DFT
>   FUNCTIONAL LDA
> &END
> > _______________________________________________
> CPMD-list mailing list
> CPMD-list at cpmd.org
> http://cpmd.org/mailman/listinfo/cpmd-list
>  


	
	
		
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