ABINIT Discussion Forums

Hi Everyone,

I have used the hydrogen molecule and hydrogen atom tutorial successfully (t25.in).

Now, I want to do the same calculation for the oxygen atom and oxygen molecule.

But I am not sure what values nsppol and spinat should have in this case.

Would someone be so kind as to tell me?
As well, are there any other parameters I need to include that are not in t25.in?

Thanks,

John

As ground state O2 is a triplet, I suppose you would set up similarly to a ferromagnet, i.e. nsppol 2, nspden 2, spinat 0.0 0.0 1.0 0.0 0.0 1.0 (this would have the spin density along +z for both oxygen atoms).

Thanks. for the help.

Obviously, I'm new to abinit.

would it be correct to say that for the oxygen atom run alone, I would use the same settings, except change 0.0 0.0 1.0 0.0 0.0 1.0 to just one triplet of 0.0 0.0 1.0?

thanks,

John

Yes, you need one triple in spinat for every atom. So just one for oxygen. Since the ground state of oxygen has nominally two unpaired spins you could set spinat to 0.0 0.0 2.0, but it doesn't matter much, you're just breaking the symmetry for the system in order to get the ground state minimization started along the right direction.