[Pw_forum] A method on defining a based-centered monoclinic cell

[yinwei_li]

> a=11.692, b=2.159, c=3.463, beta=103.7, 
>Notice that above you have an angle beta != 90, whereas in
>QE(quantum espresso) gamma != 90. Draw corresponding pictures of the two
>settings of the unit cell and you will undestand what you have to
>"swap".

I have tested in this case. with the right-hand screw rule, the lattice could be changed to:
a=3.463, b=11.692, c=2.159, gamma=103.7, the atomic positions in the unit cell was changed too.
however, during the transformation to the primitive cell in the Materials Studio, it will give a same atomic positions and lattice parameters (of the primitive cell) with the old one. therefore, I still could not get a correct structure in this way. Maybe this is because of the Materials Studio, which is not a best tool to generate the input information for PWSCF. So I want to know what tools you use to generate the input information such as atomic positions?


2009-03-10 



 ***************************************
Yinwei Li （李印威）
PHD
State Key Lab of Superhard Materials, Jilin University
2699 Qianjin Str.
130012, Changchun
P. R. China
********************************************



发件人： Tone Kokalj 
发送时间： 2009-03-09  21:53:32 
收件人： PWSCF Forum 
抄送： 
主题： Re: [Pw_forum] A method on defining a based-centered monoclinic cell 
 
On Mon, 2009-03-09 at 20:31 +0800, yinwei_li wrote:
> Sorry, everyone, MS is Materials Studio modeling.
>  
>  In fact, I found many users, as well as me, have problems on the input defining a based-centered monoclinic cell. For example, a c2m structure with 
> a=11.692, b=2.159, c=3.463, beta=103.7, 
Notice that above you have an angle beta != 90, whereas in
QE(quantum espresso) gamma != 90. Draw corresponding pictures of the two
settings of the unit cell and you will undestand what you have to
"swap".
Regards, Tone
-- 
Anton Kokalj
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 
(tel: +386-1-477-3523 // fax:+386-1-477-3822)
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