[QE-users] calculation of non stable state

[Konrad Gruszka]

Hello again,

I've tried (with success) to achieve goal using nspin=2 with combined 
with total_magnetization=2, yet the second approach using 
occupations='from_input' and OCCUPATIONS card is still without success.

I clearly understand wrong this card, I was using this (for hydrogene 
molecule):

OCCUPATIONS
1
0
1
0
----------------------
OCCUPATIONS
2
----------------------
OCCUPATIONS
2
0
----------------------
OCCUPATIONS
1 1
----------------------

...and few more. The documentation is not excessively helpful but if I 
understand the scheme in OCCUPATIONS card is:

OCCUPATIONS
x x x x        <-number of UP spins in 1s 2s 2p 3s  respectively (for 
example for first (eg. sodium) atom)
y y y y        <-number of DOWN spins in 1s 2s 2p 3s respectively (for 
first atom)
z z z z         <-number of UP spins in second atom etc..

but always I got: "strange occupations: number of electrons from 
occupations is wrong."

What is the correct input for OCCUPATIONS card for two hydriogene atoms?
Konrad




W dniu 12.06.2018 o 21:46, Lorenzo Paulatto pisze:
>
> On 06/12/2018 06:09 PM, Konrad Gruszka wrote:
>>
>> OCCUPATIONS
>> 1
>> 1
>>
>> nspin=2; and tot_magnetization=2
>>
>> Are those two inputs equivalent? 
>
> No, the first one means "one electron in the first band spin up and 
> one in the first ban spin down", which means no magnetization, or 
> tot_magnetization=0.
>
> Also note that you need to specify nspin=2 in both cases. Also, in the 
> first case, setting nspin=1 would have exactly the same effect (for 
> cheaper, not that it matters in H2 molecule) as the occupations are 
> the same for both spin polarizations.
>
>> Also, will this give proper results when including spin-orbit with 
>> full relativistic pseudopotential or do I need to do it another way?
>
> I'm not sure if occupations="from_input" works with non-colinear 
> magnetization. I'm quite sure that tot_magnetization does NOT, instead 
> you have to use fixed_magnetization="total" and set the 
> tot_magnetization vector. This method is powerful, a bit complicated, 
> but quite well documented.
>
>
>

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