Re: GSAS - p 63/m m c

[apu]

Dear (Sir) Stefano Agrestini,

Thank you for your help. Now I am getting good result, but I am confused also. I will be grateful to you tell me how do you determine the atom coordinate as (1/3, 2/3, 1/4) in case of Zirconium (p 63/m m c), whereas the position of the atoms are (0,0,0) and (2/3, 1/3, 1/2).

What is the general rule for supplying the atoms coordinate in GSAS? Is there any literature(help) on this topic?

Thanking you.

With best regards,

Apu 

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Apu Sarkar
Research Fellow
Variable Energy Cyclotron Centre
Kolkata 700 064
phone: 91-33-2337-1230 (extn. 3190)
Fax: 91-33-2334-6871
INDIA
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----- Original Message -----

From: "Stefano Agrestini (Bianconi)" <[EMAIL PROTECTED]>

Date: Saturday, October 2, 2004 11:05 pm

Subject: Re: GSAS - p 63/m m c

> Dear Apu
> The correct information are:
> **Zr**
> Zirconium Metal hexagonal (Mg-type)
> 10.00 .010 1 .500
> 3.2320 3.2320 5.1470 90.0000 90.0000 120.0000
> P 63/M M C 194
> ZR 2c .3333 .6667 .2500 1.000
>
>
> Therefore you must give to GSAS only the 1/3 2/3 1/4 position. All the
> other equivalent positions will be created automatically by GSAS
> throughthe space group P 63/m m c.
>
> Stefano Agrestini
>
> On Sat, 2 Oct 2004 [EMAIL PROTECTED] wrote:
>
> >
> >
> > Dear All,
> >
> > I am trying to do Rietveld refinement of  Zirconium using GSAS.
> Its space
> > group is p 63/mmc (194). It is a hexagonal closed packed system
> with two
> > atoms per unit cell. Position of the one atom is (0, 0, 0) and
> that of
> > the other is (2/3, 1/3, 1/2).
> <>
> > I am also giving the atom coordinates i.e. x,y,z as (0, 0, 0)
> for Zr1 and
> > (0.666, 0.333, 0.5) for ZR2 in GSAS.
> >
> > I think I am doing wrong because it is giving very bad result..
> >
> > Please suggest what should I give as the atom coordinates.
> >
> > Thanking you all.
> >
> > Regards,
> >
> > Apu
> >
> > /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> > Apu Sarkar
> > Research Fellow
> > Variable Energy Cyclotron Centre
> > Kolkata 700 064
> > phone: 91-33-2337-1230 (extn. 3190)
> > Fax: 91-33-2334-6871
> > INDIA
> > /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> >
> >
> >
> >
>
>
>
>