[Wien] O2 in triplet state?

[chin Sabsu]

 Dear Sir,
I am thankful for the confirmation of the state of O2 molecule.

I am tried to reproduce some results for oxygen deficient system but I see from my data that my system is not stable.

I started from the given lattice parameters, exact functionals,(GGA, as suggested in the paper) rmt k-mesh etc.

The authors did not mention anything about how they have calculated the formation energy and atomization energy. In my previous post your reply with some notes, I followed the same data to simulate ground state energy of O2 and O but still am not getting the reasonable results.

As I used data for O2 from FAQ and also tried according to the information given in the literature paper.

I see there should not be any issue in calculating the O2 energy.


My doubt is somewhere in the calculation of O (-sp) with below data:



Title
F   LATTICE,NONEQUIV.ATOMS:  1
MODE OF CALC=RELA unit=bohr
 28.345900 28.345900 28.345900 90.000000 90.000000 90.000000
ATOM   1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 2
O          NPT=  781  R0=0.00010000 RMT= 1.65000     Z:  8.000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
  48      NUMBER OF SYMMETRY OPERATIONS



and
O
He 3  
2,-1,1.0  N
2,-1,1.0  N
2, 1,1.0  N
2, 1,1.0  N
2,-2,2.0  N
2,-2,0.0  N
****
****         END of input (instgen_lapw)


below are data from O2 and O-atom with GGA

 
| O_atom_rmt_1.75_rkmax_7 | -149.86322972 |
| O_atom_rmt_1.1_rmkax_5.5 | -150.0869798 |
| O2_mol_bondlength_1.21_rkmax_5.5 | -300.1077091 |
| [O2_mol_1.21]\2 | -150.05385455 |
| O3_mol_1.21 | -450.16156365 |
| O2_mol_bondlength_1.219_rkmax_4.6 | -299.95534741 |
| [O2_mol_1.219]\2 | -149.977673705 |
| O3_mol_1.219 | -449.933021115 |

 

In his previous post in response of my query, Prof. Alay advice about calculating the ground state energy of O-atom by considering O atom cell as orthorhombic to avoid any issue occurring from the occupancy of P-states of O-atom. His statement is quoted below:


"Computing the atomic energies of atoms like N and P in an FCC cell is ok, however for O atom the high symmetry of the FCC cell results in 1/3  occupancies (for the 4th p electron of O) in the spin down case. Only using a lower symmetry cell (orthorhombic) for O atom eliminates this issue." 
Could you please advise me whether my above data looks good or not.

If I have to follow the suggestion advanced by Prof. Alay, then how to make an Orthorhombic cell for O-atom?

I have done three calculations for three materials but I am not getting the atomization and formation energy of O2 while the author reported similar statements in his papers.


Please help me to simulate the ground state energy of O2 and O taking care of occupancy of P orbitals.

Please let me know what additional information I can provide.


thank you very much for a big help.

 Chin S.



 
    On Monday, 23 April, 2018, 10:32:22 AM IST, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote:  
 
 This is the configuration for a spin-polarized O atom.

And yes, this starting configuration will lead to the triplet state of 
O2 (when you perform spin-polarized calculations.)

Am 22.04.2018 um 08:16 schrieb chin Sabsu:
> Dear Users,
> 
> 
> Could you please advice me whether below *.inst form O2 in triplet 
> state? three e- in dn and one e- in up state?
> 
> 
> O
> He 3
> 2,-1,1.0  N
> 2,-1,1.0  N
> 2, 1,1.0  N
> 2, 1,1.0  N
> 2,-2,2.0  N
> 2,-2,0.0  N
> ****
> ****         END of input (instgen_lapw)
> 
> 
> Thanks and best regards,
> 
> Chin S.
> 
> 
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-- 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300            FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW: 
http://www.imc.tuwien.ac.at/tc_blaha------------------------------------------------------------------------- 

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