[Wien] (no subject)

[Peter Blaha]

I'm afraid I cannot help much more by an email conversation.

Just play with supercell and visualize (xcrysden) the resulting structures
(switch on the "display crystal cells", so that you "see" the vacuum).

You should easily find out what the different options do.

K.V.P.Lata schrieb:
> Thankyou very much for the suggestions. I tried both, but didn't get
> the structure I was hoping
> to get. Second one seemed simpler. About the second option, where I
> generate two bulk slabs, one for Fe and one for MgO,
> I have some questions.
> 
> 1. I first generated the Fe struct input, then used the supercell
> program to introduce vacuum
> towards the bottom of the Fe slab. In this, for simplicity I used 3
> cells along only z-direction,
> and the vacuum needs to be introduced after the third one
> (bottommost). I want to attach the MgO
> slab in the vacuum. You had written that the vaccuum needs to be big
> enough to accommodate
> the MgO slab. I do not know how to control *from* which point *to*
> which point the vaccuum is needed.
> In other words I imagine that I want all Fe atoms arranged till some
> value of 'z' and the rest of the cell
> should be vaccuum, of same size as MgO whcih I will attach later. But
> whatever I use for the magnitude of
> vaccuum (only along z), it is pushed towards the end of the slab and
> vaccuum is introduced only in the last layer !
> I dont know what mistake I am doing.
> 
> Could you tell me what is the 'repeat atoms' for and what is the
> problem in the abov eprocedure ? Also, I am facing a problem
> in shifting the atoms. Since my entire Fe slab is ~ 8 Angstroms along
> z, with (0,0,0) at the top of the slab,
> I want to shift the MgO slab by this amount. I use the optional shift.
> If the lattice constant of MgO ~ 4.12
> Angstroms, then whatever shift I input as fractional coordinates, the
> MgO block is getting cut. I thought
> I am shifting the origin along the Z-axis, but that doesnt seem to be happening.
> 
> Eagerly waiting for your response,
> 
> Best,
> Krish
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> Wien at zeus.theochem.tuwien.ac.at
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                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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