[Wien] [Wien2k Users] The problem of lattice stability of tetragonal lattice

[Ghosh SUDDHASATTWA]

Dear Wien2k users, 

 

When we consider Zr (hcp) in a tetragonal or orthorhombic lattice, 

we have to consider the c/a optimization. 

Now, we can consider Zr in tetragonal lattice with 1 or more than 1
equivalant point also. 

But both these structures are tetragonal. 

Now the difference ENE(Zr, hcp)-ENE(Zr,tetragonal, one equivalent position) 

and ENE(Zr,hcp)-ENE(Zr,tetragonal, more than 1 equivalent position ) both
would be different (after c/a optimization...) 

 

Both are the measure of the lattice stability for a tetragonal lattice. In
both the cases I get a smooth variation of energy and c/a % change. But I am
not sure which one to take. 

There should be only one value of lattice stability irrespective of 1 atomic
position or more than 1 positions. Am I right here? 

What should be the right approach? 

I envisage the following approach 

1. c/a optimization. 

2. With the equilibrium lattice parameters, force minimize using mini

3. With the equilibrium lattice parameters and equilibrium atomic positions,
get the energy vs c/a. plot

Is the approach right? 

 

Suddhasattwa Ghosh

 

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20100426/0284f7c8/attachment.htm>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: ATT00033.txt
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20100426/0284f7c8/attachment.txt>