[QE-users] scf of orthorhombic structure

[Pooja Vyas]

Then according to it, shouldn't I be using the formula V=abc?

On Tue, Oct 26, 2021 at 3:47 PM Pooja Vyas <poojavyas595 at gmail.com> wrote:

> Dear user,
> my lattice parameters are in agreement with
> https://materialsproject.org/materials/mp-560885/. For which I've used
> ibrav=8 which is for primitive.
>
> On Tue, Oct 26, 2021 at 3:35 PM Kazume NISHIDATE <nisidate at iwate-u.ac.jp>
> wrote:
>
>>
>> I don't know what type of primitive vectors you are choosing, but the
>> difference of the volumes may originate from the difference of their
>> definitions.
>>
>> The simple orthorhombic Bravais lattice is identical to the
>> conventional cell with the volume of V=abc. While the volume of the
>> primitive face-centered orthorhombic unit cell is V=abc/4.
>> In your system, 45x4 => 180 is close to your value of 176.
>>
>> see eg.
>> http://aflowlib.org/prototype-encyclopedia/orthorhombic_lattice.html
>>
>> best regards
>> kazume NISHIDATE
>> 敬具 西館数芽
>>
>> nisidate at iwate-u.ac.jp
>> kazume.nishidate at gmail.com
>>
>>
>> 2021年10月26日(火) 17:52 Pooja Vyas <poojavyas595 at gmail.com>:
>>
>>> Dear users,
>>>
>>> I required optimized lattice parameters of orthorhombic CaSiO3 for which
>>> I executed variable cell relaxation. The equilibrium volume obtained was
>>> 176 ang^3 while the reported ones are around 45 ang^3. The optimized
>>> lattice constant agrees well with reported data. Can I know how to convert
>>> lattice parameters a, b, c of orthorhombic CaSiO3 into volume?
>>>
>>> Also If I require a lattice constant-energy curve, should I change all
>>> lattice constants a, b, and c with equal step size and run an scf at all
>>> points?
>>>
>>> Regards.
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>>
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>
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