[Pw_forum] vc-relax lattice constance optimzition

[Paolo Giannozzi]

Look for the stress in the output, in particular for suspicious
messages. I doubt that the stress is implemented with meta-GGA. No
stress, no cell optimization.

Paolo

On Tue, Jun 27, 2017 at 9:04 PM, Hong Tang <tanghong992 at gmail.com> wrote:
> Hi, All:
>
> I am very grateful somebody can help me the following problem.
>
> I am trying to use QE to do Si  crystal lattice optimization. please see the
> input of my file.  However, after calculations, I sue grep -n "volume"
> Si.rx.out , I got results that always show the volume of the unit cell
> doesn't change.
> [hongtang at login3 results]$ grep -n "volume" Si.rx.out
> 39:     unit-cell volume          =     265.3020 (a.u.)^3
> 1812:     new unit-cell volume =    265.30200 a.u.^3 (    39.31370 Ang^3 )
> 3146:     new unit-cell volume =    265.30200 a.u.^3 (    39.31370 Ang^3 )
> 4462:     new unit-cell volume =    265.30200 a.u.^3 (    39.31370 Ang^3 )
> 5776:     new unit-cell volume =    265.30200 a.u.^3 (    39.31370 Ang^3 )
> 5807:     unit-cell volume          =     265.3020 (a.u.)^3
> ________________________________________________
>
> input
> &CONTROL
>   calculation = "vc-relax",
>   pseudo_dir  = "/home/hongtang/tmqe6.0/pseudo",
>   prefix      = "Si",
>   outdir      = "/home/hongtang/tmqe6.0/tempdir",
>   dt          = 100,
>   verbosity   = 'high',
>   tstress     = .true.
>   tprnfor     = .true.
>   nstep       = 900,
>   etot_conv_thr = 1.D-5,
>   forc_conv_thr  = 1.D-4,
> /
> &SYSTEM
>   ibrav       = 2,
>   celldm(1)   = 10.2D0,
>   nat         = 2,
>   ntyp        = 1,
>   ecutwfc     = 60.D0,
>   nosym = .true.
> /
> &ELECTRONS
>   conv_thr   = 1.D-7,
>   mixing_beta = 0.7D0,
>   electron_maxstep  = 300
> /
> &IONS
>    bfgs_ndim      = 1,
>    trust_radius_max = 1.0D0,
>    trust_radius_ini  = 0.6D0,
>    trust_radius_min = 0.1D0,
> /
> &CELL
>   cell_dynamics = 'bfgs',
> /
> ATOMIC_SPECIES
> Si 28.09 Si.tpss-mt.UPF
> ATOMIC_POSITIONS
> Si 0.00 0.00 0.00
> Si 0.25 0.26 0.24
> K_POINTS {automatic}
> 7 7 7 0 0 0
>
>
>
>
>
>
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222