Thanks Giuseppe,
I’ll give it a try, I didn’t think about setting the occupation from input.
Thank you for your help.
Best,
Filippo
Filippo Savazzi, PhD Student
Politecnico di Torino, Torino, Italy
> On 21 Nov 2018, at 19:00, Giuseppe Mattioli <giuseppe.matti...@ism.cnr.it>
> wrote:
>
>
> Dear Filippo
> Isolated open-shell atoms are tricky. Please look here for hints
>
> yourpathtoQE6.3/PW/examples/example05
>
> HTH
> Giuseppe
>
> Quoting Filippo Savazzi <filo.sava...@gmail.com>:
>
>> Dear QE users,
>>
>> I’m Filippo Savazzi, a PhD student from Politecnico di Torino, Italy.
>> I’m using QE since a couple of years, and just browsing the archives of this
>> mailing list or enquiring the mighty google I’ve been lucky enough that this
>> is actually the first time I have to post a question.
>> Thanks everybody for the indirect support you gave me in these years.
>>
>> I’m calculating absorption energies of oxygen on a coronene molecule, as
>> part of a little evaluation of different available XC functionals that I’m
>> doing. I’m calculating the absorption energy both with respect to the
>> molecular oxygen and with atomic oxygen.
>> My problems arise when I try to calculate the energy of a single atom of
>> oxygen using SCAN. In this case the energy diverges until the SCF fails. I
>> have no troubles running the calculation on the actual system (coronene +
>> bridged O), neither on a molecular oxygen (triplet O2); the issue is just
>> localised on the single oxygen atom. My first guess was that the
>> implementation of SCAN has either troubles in dealing with isolated systems
>> or with spin polarization, but I ruled out these issues when I was able to
>> calculate the single point energy of an oxygen molecule. Are you aware of
>> any other problems using SCAN in these conditions?
>> In the following I attach the input for pw.x I’m using, as well as a brief
>> example of the SCF part in the output. I already played with cell dimension
>> (thinking too much vacuum could have been the problem), as well as with
>> ecutwfc and ecutrho (so indirectly with the integration grid), and then,
>> just to give it a chance, with the diagonalization method and beta-mixing.
>>
>> Thank you in advance for your attention.
>>
>> Best,
>> Filippo
>>
>>
>> Filippo Savazzi, PhD Student
>> Politecnico di Torino, Torino, Italy
>>
>>
>>
>>
>> &CONTROL
>> calculation = ’scf',
>> restart_mode='from_scratch',
>> pseudo_dir = '/home/filippo/pseudo',
>> outdir='./tmp_o',
>> prefix='oxy',
>> /
>> &SYSTEM
>> ibrav=6,
>> celldm(1)=20,
>> celldm(3)=1,
>> nat=1,
>> ntyp=1,
>> input_dft='scan',
>> ecutwfc=100,
>> tot_magnetization=2,
>> nspin=2,
>> /
>> &ELECTRONS
>> diagonalization = 'cg',
>> electron_maxstep = 300,
>> mixing_mode = 'local-TF',
>> mixing_beta = 0.7,
>> conv_thr = 1.0d-7,
>> /
>> &IONS
>> ion_dynamics='damp',
>> upscale=1000,
>> /
>> ATOMIC_SPECIES
>> O 15.99 O_ONCV_PBE-1.0.upf
>> ATOMIC_POSITIONS {angstrom}
>> O 0.0000 0.0000 0.0000
>> K_POINTS{gamma}
>>
>>
>>
>>
>> EXTRACT OF OUTPUT:
>>
>> Dense grid: 540376 G-vectors FFT dimensions: ( 128, 128, 128)
>>
>> Estimated max dynamical RAM per process > 116.06 MB
>>
>> Estimated total dynamical RAM > 1.36 GB
>> Generating pointlists ...
>> new r_m : 0.4125 (alat units) 8.2500 (a.u.) for type 1
>>
>> Initial potential from superposition of free atoms
>>
>> starting charge 5.99905, renormalised to 6.00000
>>
>> negative rho (up,down): 4.917E-05 4.917E-05
>> Starting wfcs are random
>>
>> total cpu time spent up to now is 3.1 secs
>>
>> Self-consistent Calculation
>>
>> iteration # 1 ecut= 100.00 Ry beta= 0.70
>> CG style diagonalization
>> ethr = 1.00E-02, avg # of iterations = 9.6
>>
>> negative rho (up,down): 1.044E-03 1.363E-03
>>
>> total cpu time spent up to now is 240.5 secs
>>
>> total energy = 2429.63502350 Ry
>> Harris-Foulkes estimate = -31.41616940 Ry
>> estimated scf accuracy < 3.28037744 Ry
>>
>> total magnetization = 2.00 Bohr mag/cell
>> absolute magnetization = 2.00 Bohr mag/cell
>>
>> iteration # 2 ecut= 100.00 Ry beta= 0.70
>> CG style diagonalization
>> c_bands: 4 eigenvalues not converged
>> ethr = 1.00E-02, avg # of iterations = 13.6
>>
>> negative rho (up,down): 2.824E-03 3.815E-03
>>
>> total cpu time spent up to now is 331.7 secs
>>
>> total energy = 33638.43350785 Ry
>> Harris-Foulkes estimate = 318.68713998 Ry
>> estimated scf accuracy < 0.37936007 Ry
>>
>> total magnetization = 2.00 Bohr mag/cell
>> absolute magnetization = 2.00 Bohr mag/cell
>
>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> Via Salaria Km 29,300 - C.P. 10
> I-00015 - Monterotondo Scalo (RM)
> Mob (*preferred*) +39 373 7305625
> Tel + 39 06 90672342 - Fax +39 06 90672316
> E-mail: <giuseppe.matti...@ism.cnr.it>
>
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