[Wien] error in lapw0

[Peter Blaha]

There's no problem with 3 different Oxygens. Just make them equal.

If Gmin > Gmax: increase GMAX (edit case.in2(c))

PS: Are you sure:  Gmin > Gmax when you reduce RKMAX (case.in1(c)) to 3 or 3.5
(that's what you need for a small H-sphere !)

> I did, I uesd suggestions from setrmt, however the problem is that I have 3 
> non-equivalent oxygen, one of them is in the vast channel formed by chains 
> of VO6 octahedra. The hydrogen forms O-H bond of length of 0.96A as deduced 
> from neutrons diffraction. If I leave it automatically, then gmin>gmax, i.e. 
> it is very sensitive to RMT of O2 and H. Should I try to increase Rmax or 
> something else?
> Regards,
> Igor
> 
> ----- Original Message ----- 
> From: "Peter Blaha" <pblaha at theochem.tuwien.ac.at>
> To: "A Mailing list for WIEN2k users" <wien at zeus.theochem.tuwien.ac.at>
> Sent: Tuesday, June 05, 2007 9:04 AM
> Subject: Re: [Wien] error in lapw0
> 
> 
>> Why don't you use the suggestions from setrmt during initialization (or 
>> first
>> point in structgen/w2web) ?
>>
>> a) All Radii of a particular atom must be the same. So choose ALL Oxygen
>> spheres the same.
>> b) H spheres should be "half" as big as their partners. So with a O2-H 
>> distance
>> near 1.7 bohr choose 1.15 and 0.55 (or similar).
>>
>> Then run a "complete" initialization!! Don't "skip" certain steps (like
>> dstart), otherwise case.in0 might not be correct and you get your error in 
>> lapw0
>>
>> Igor Djerdj schrieb:
>>>
>>> Dear all,
>>>  I am trying to perform calculation on the system which comprises V, O
>>> and H.  I took into account tips and tricks which are written in the
>>> manual or faq regarding Rmax =3 or 4, Gmax up to 25, and I adjusted RMT
>>> in order to get gmin<gmax. The latter condition is fullfiled if I choose
>>> for RMTs:
>>> V 1.77
>>> O1 1.12
>>> O2 0.89
>>> O3 1.12
>>> H  0.8.
>>> H is attached to O2. Especially, RMt of H and O2 are very sensitive to
>>> condition gmin<gmax. Then I run scf and meet after 1 cycle with the
>>> error in lapw0:
>>> IFFT TOO SMALL IN XCPOT3
>>> 2*(KKK+1) LARGER THAN IFFT PARAMETER IN XCPOT3
>>> KKK  0 54 0
>>>         0 54 0
>>> IFFT 108 108 80.
>>> What should I do?
>>> Regards,
>>> Igor
>>>
>>>
>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
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>> -- 
>>
>>                                       P.Blaha
>> --------------------------------------------------------------------------
>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>> Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
>> Email: blaha at theochem.tuwien.ac.at    WWW: 
>> http://info.tuwien.ac.at/theochem/
>> --------------------------------------------------------------------------
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
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> 
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-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
--------------------------------------------------------------------------