Dear wien2k users,
I have a query regarding volume optimization in wien2k. "Option 1"
optimizes the volume by keeping a:b:c = constant. Now my question is:
in which case this "Option 1" is applicable?...is it only applicable for
cubic symmetry?
Any response in this regard will be helpful for
I have a query regarding volume optimization in wien2k. "Option 1"
optimizes the volume by keeping a:b:c = constant. Now my question is:
in which case this "Option 1" is applicable?...is it only applicable for
cubic symmetry?
You can use it for any crystal. Very often, the total energy will
Dear Stefaan Cottenier Sir,
Thank you very much for your response. We got our answer.
with regards,
On Wed, Jun 19, 2013 at 3:03 PM, Stefaan Cottenier <
stefaan.cotten...@ugent.be> wrote:
>
> I have a query regarding volume optimization in wien2k. "Option 1"
>> optimizes the vol
Dear wien2k community,
I'm puzzled by the following observation about convergence tests for a
molecular crystal built entirely from O2-molecules (two O2-molecules per
unit cell): the basis set needs to be particularly large before even the
the volume of the unit cell can be reliably determine
-- Forwarded message --
From: shamik chakrabarti
Date: Wed, Jun 19, 2013 at 6:51 PM
Subject: Re: [Wien] Question regarding volume optimization
To: Shamik Chakrabarti
Dear Stefan Cottenier Sir,
I have another question regarding optimization of a,b,c (3D case)
using "option
What you find is about consistent with my observations. I would say
that for an RMT of 0.5 a fairly good calculation is roughly an RKMAX
of 3.5, and for an RMT of 2.0 an RKMAX of 8. As a rough guide this
corresponds to (linear approximation)
RKMAX = 3.5 + 3*(RMT_min-0.5)
This is a crude estimate,
What you find is about consistent with my observations. I would say
that for an RMT of 0.5 a fairly good calculation is roughly an RKMAX
of 3.5, and for an RMT of 2.0 an RKMAX of 8.
It depends of course on what you're looking at, but these look to be
rather conservative values. The default RK
> This would imply that simply rescaling the RKMAX ("RKMAX=8.0 for RMT=2.0
> corresponds to RKMAX=4.0 for RMT=1.0") yields a calculation that is
> effectively *less* accurate.
Yes, I am 99.9% certain that it is not a simple linear scaling. If it
was then with H and an RMT of 0.5 then RKMAX=1.75 wo
-- Forwarded message --
From: shamik chakrabarti
Date: Wed, Jun 19, 2013 at 6:52 PM
Subject: Fwd: [Wien] Question regarding volume optimization
To: A Mailing list for WIEN2k users
-- Forwarded message --
From: shamik chakrabarti
Date: Wed, Jun 19, 2013 at 6:51
Dear Prof. Blaha and WIEN2k users,
I am happy to announce here the first version of the ElaStic code is
available. ElaStic is an open-source Python implementation for the
calculations of elastic constants of crystalline materials. It can be used
to obtain full second-order elastic tensors for all
Dear Prof. Blaha and WIEN2k users,
I am happy to announce here the first version of the ElaStic code is
available. ElaStic is an open-source Python implementation for the
calculations of elastic constants of crystalline materials. It can be used
to obtain full second-order elastic tensors for all
Well, at http://www.wien2k.at/reg_user/faq/rkmax.html it even says you
need RKmax=6.5 for O.
On the other hand I do not understand the following:
>> The table lists the RKMax value, the matrix size, the corresponding
>> RKMax if the muffin tin radius would be 2.0 (that gives a better feeling
Dear all,
Perhaps it is worthwhile to reiterate the basic reason APW based methods
typically use RKmax to determine sufficient planewave convergence rather than
Kmax (for the less experienced users, at least): for a given atom, the
wavefunctions become more rapidly oscillatory, in both angular
[note: short survey included -- you're kindly asked to fill it out]
The combined answers by Marks/Blaha/Pask were very instructive. Thanks!
It made me aware of a misconception I have been carrying with me for
years: RKMax is more than just a warped way of presenting K_max. Taking
K_max as t
I have another question regarding optimization of a,b,c (3D case)
using "option 6". We can generate several structures by varying say 1%
of the initial lattice parameters. Then my question is
(1) how those 3 lattice parameters are varied to generate structures?
say, two successive files
What you say may be appropriate for a single element.
But...to complicate the issue, suppose I have bulk MgO, H2O (gas) &
bulk Mg(OH)2 where the RMTs are Mg=1.6, O=1.2, H=0.5 and I want to
calculate the thermodynamics of the reaction MgO+H2O -> Mg(OH)2. In
such a case a fixed RKmax will give diffe
> What you say may be appropriate for a single element.
In the context of multiple species, one must consider the most limiting
species, i.e., the one which requires largest RKmax to converge to desired
accuracy. That RKmax is then sufficient for all.
> But...to complicate the issue, suppose I
Remember, for MgO and Mg(OH)2 in the example I gave Rmt (the minimum
RMT for all the atoms) is not the same.
On Wed, Jun 19, 2013 at 4:27 PM, Pask, John E. wrote:
>
>> What you say may be appropriate for a single element.
>
> In the context of multiple species, one must consider the most limiting
> Remember, for MgO and Mg(OH)2 in the example I gave Rmt (the minimum
> RMT for all the atoms) is not the same.
Yes, if that is the case, that is important indeed. My answer assumed the fixed
Rmt's you specified (Mg=1.6, O=1.2, H=0.5) present in calculations.
John
>
> On Wed, Jun 19, 2013 a
Dear Stefaan Cottenier Sir,
Thank you for your response. It will be helpful for us.
with regards,
On Thu, Jun 20, 2013 at 2:05 AM, Stefaan Cottenier <
stefaan.cotten...@ugent.be> wrote:
>
> I have another question regarding optimization of a,b,c (3D case)
>> using "option
When we talk about "fixed" RKmax, it is better to talk about fixed
RKmax(atom).
Lets take your example:
We do H2O with RKmax=3 (case.in1) and the RMTs listed below (1.2 ad
0.5). This statement implies RKmax(H)= 3, but RKmax(O)= 1.2/0.5*3= 7.2 !!!
Thus one would do H2O and Mg(OH)2 with "RKMAX
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