Dear Wien2k users,
We consider that the stable ground state of a metal is bcc. The fcc
structure is the high temperature phase. To calculate the enthalpy of
transformation of the fcc to bcc, we consider the following
Enthalpy of transformation =ENE(fcc)-ENE(bcc)
Now for this above equati
> We consider that the stable ground state of a metal is bcc. The fcc
> structure is the high temperature phase. To calculate the enthalpy of
> transformation of the fcc to bcc, we consider the following
>
> Enthalpy of transformation =ENE(fcc)-ENE(bcc)
>
> Now for this above equation, do we ha
: Friday, February 19, 2010 1:33 PM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] [Wien2k User Group] Lattice stability in bcc, fcc and
hcp and other crystal structures
> We consider that the stable ground state of a metal is bcc. The fcc
> structure is the high temperature pha
> Is there any way out to simultaneously optimize the lattice parameters and
> the internal coordinates in w2web?
You might read the structure optimization notes at
http://www.wien2k.at/reg_user/textbooks/ (in particular Sec. 5)
Stefaan
bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Ghosh
SUDDHASATTWA
Sent: Friday, February 19, 2010 3:52 PM
To: 'A Mailing list for WIEN2k users'
Subject: Re: [Wien] [Wien2k User Group] Lattice stability in bcc,fcc and hcp
and other crystal structures
Thank you Stefaan,
Is there any way o
> You have mentioned fcc or bcc. Why or?
I assumed you mentioned elemental materials (like fcc Ni, or bcc V).
There are no modifiable internal positions in such a structure, hence
nothing to do for min_lapw. But :ENE does change if you change the cell
size and/or shape (here: just the lattice
stability in bcc, fcc and
hcp and other crystal structures
> You have mentioned fcc or bcc. Why or?
I assumed you mentioned elemental materials (like fcc Ni, or bcc V).
There are no modifiable internal positions in such a structure, hence
nothing to do for min_lapw. But :ENE does change if
> 1. I want optimized positions in case of experimentally known crystal
> structures. Does it really help? Is it worth doing? I may be wrong or may be
> doing what is not required.
>
> 2. I want to do only internal coordinates optimization for metastable
> phases. Is it incomplete?
It all depe
t for WIEN2k users
Subject: Re: [Wien] [Wien2k User Group] Lattice stability in bcc, fcc and
hcp and other crystal structures
> 1. I want optimized positions in case of experimentally known crystal
> structures. Does it really help? Is it worth doing? I may be wrong or may
be
> doi
> The stable phases of uranium are C-centered orthorhombic (alpha), primitive
> tetragonal(beta) and fcc (gamma).
> Getting the atomic positions of these phases from ICSD, I can calculate the
> ENE (ground state energy). I need not do any min_lapw since these are stable
> phases.
That last statem
you on this topic.
Suddhasattwa
-Original Message-
From: wien-boun...@zeus.theochem.tuwien.ac.at
[mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Stefaan
Cottenier
Sent: Sunday, February 21, 2010 1:43 AM
To: wien at zeus.theochem.tuwien.ac.at
Subject: Re: [Wien]
> I assume U is in the hcp Zr ( we know the lattice parameters of Zr in hcp
> from ICSD)
> The atomic positions are 0.333 0.667 and 0.25
> So I imagine U to have the same lattice parameters and then I do min_lapw.
> I optimize only the internal coordinates; I try to minimize the forces
-Original Message-
From: wien-boun...@zeus.theochem.tuwien.ac.at
[mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Stefaan
Cottenier
Sent: Monday, February 22, 2010 1:30 PM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] [Wien2k User Group] Lattice stability in bcc
> Thank you very much for the answer. So the conclusions are (correct me if I
> am wrong)
>
> 1. ENE (total energy in Wien2k) of stable phases also should be calculated
> after volume optimization.
> 2. The same holds for high temperature phases as well.
> 3. For metastable phases, volume opti
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