[QE-users] Forces are oscillating for P

[Eduardo Menendez]

Bhamu,
Set the input parameters trust_radius_min and trust_radius_ini to values
smaller than default.
If this does not solve the problem, increase ecutrho.

Eduardo Menendez Proupin
--------------------------------------
I assume that you know enough never to evaluate a polynomial this way:
p=c(0)+c(1)*x+c(2)*x**2+c(3)*x**3+c(4)*x**4
NR, Sect. 5.3 Polynomials and Rational Functions


El mié, 4 ago 2021 a las 6:01, <users-request at lists.quantum-espresso.org>
escribió:

> S
> ---------- Forwarded message ----------
> From: "Dr. K. C. Bhamu" <kcbhamu85 at gmail.com>
> To: Quantum Espresso users Forum <users at lists.quantum-espresso.org>
> Cc:
> Bcc:
> Date: Tue, 3 Aug 2021 16:42:52 +0530
> Subject: [QE-users] Forces are oscillating for P
> Dear QE Users,
> I am trying to run phosphorus  with QE_6.4 but the forces are
> oscillating between two values as shown below:
> scf.in.out:     Total force =     0.008737     Total SCF correction =
> 0.000002
> scf.in.out:     Total force =     0.014135     Total SCF correction =
> 0.000002
> scf.in.out:     Total force =     0.008737     Total SCF correction =
> 0.000002
> scf.in.out:     Total force =     0.014135     Total SCF correction =
> 0.000002
>
> Could you please advise me on how can I handle this?
> Below is my input file.
>
> &CONTROL
>   calculation = 'vc-relax'
>                etot_conv_thr = 0.0001
>                forc_conv_thr = 0.001
>   outdir = './tmp'
>   prefix = 'pwscf'
>   pseudo_dir = './PPs'
>   tprnfor = .true.
>   tstress = .true.
> /
> &SYSTEM
>   degauss =   1.4699723600d-02
>   ecutrho =   4.5000000000d+02
>   ecutwfc =   4.5000000000d+01
>   ibrav = 0
>   nat = 24
>   nosym = .false.
>   ntyp = 1
>   occupations = 'smearing'
>   smearing = 'cold'
>
> /
> &ELECTRONS
>   conv_thr =   1.0000000000d-010
>   electron_maxstep = 100
>   mixing_beta =   3.0000000000d-01
> /
> &IONS
>                 ion_dynamics = 'bfgs'
>  /
> &CELL
> /
> ATOMIC_SPECIES
>   P 30.973800d0 P.pbe-n-rrkjus_psl.1.0.0.UPF
> ATOMIC_POSITIONS crystal
> P            0.0720580000       0.0022250000       0.1868190000
> P            0.9279420000       0.9977750000       0.8131810000
> P            0.8504670000       0.9529930000       0.3120770000
> P            0.1495330000       0.0470070000       0.6879230000
> P            0.0068430000       0.1349530000       0.3091570000
> P            0.9931570000       0.8650470000       0.6908430000
> P            0.2219280000       0.0115050000       0.3669270000
> P            0.7780720000       0.9884950000       0.6330730000
> P            0.7635850000       0.3682920000       0.0575230000
> P            0.2364150000       0.6317080000       0.9424770000
> P            0.5925840000       0.1861370000       0.0348950000
> P            0.4074160000       0.8138630000       0.9651050000
> P            0.5138310000       0.3055910000       0.1659300000
> P            0.4861690000       0.6944090000       0.8340700000
> P            0.3968840000       0.3201140000       0.9858140000
> P            0.6031160000       0.6798860000       0.0141860000
> P            0.2968830000       0.6828830000       0.4634480000
> P            0.7031170000       0.3171170000       0.5365520000
> P            0.9475880000       0.6271520000       0.3678240000
> P            0.0524120000       0.3728480000       0.6321760000
> P            0.2012840000       0.5152940000       0.3599540000
> P            0.7987160000       0.4847060000       0.6400460000
> P            0.2365190000       0.6760260000       0.2774930000
> P            0.7634810000       0.3239740000       0.7225070000
> K_POINTS automatic
> 6 3 3 0 0 0
> CELL_PARAMETERS angstrom
>       6.0247890000       0.0000000000       0.0000000000
>      -2.0978219998      11.6760139950       0.0000000000
>      -1.8239009989      -1.2036659990      11.8186999976
>
>
> Regards
> Bhamu
>
>
>
>
>
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