[Pw_forum] structure oscillating with vc-md

[Amin Torabi]

Dear QE users,

Will you please do me a favor and take a look at my input file, below.
The total energy and force do not converge and keep oscillating...
I have tried different dt (between 20-70) and wmass, and still not able to
relax the structure
Any comment on my the input_cards here (k-point,ecut,pp,conv...?)

Many thanks



&CONTROL
        calculation     = 'vc-md'
        pseudo_dir      = './'
        outdir          = './'
        prefix          = 'dt20'
        tstress         = .true
        tprnfor         = .true
        nstep           = 100
        dt              = 20
/
&SYSTEM
        ibrav           = 12
        celldm(1)       = 8.3147
        celldm(2)       = 1.3
        celldm(3)       = 1.4772
        celldm(4)       = -0.260
        nat             = 16
        ntyp            = 2
        ecutwfc         = 85
        ecutrho         = 1100
        input_dft       = 'pbesol'
        nosym           = .true
/
&ELECTRONS
        conv_thr        = 1.0D-9
/
&IONS
        pot_extrapolation='second-order'
        wfc_extrapolation='second-order'
        ion_temperature = 'rescaling'
        tempw           = 300
/
&CELL
        press           = 0
        cell_dynamics   = 'w'
        wmass           = 4.2
/
ATOMIC_SPECIES
 B  10.811    B.pbe-n-van.UPF
 H  1.00794   H.pbe-van_bm.UPF
ATOMIC_POSITIONS crystal
B        0.005259620   0.145596712   0.040564862
H       -0.199830030   0.176142715   0.150841828
H        0.217291388   0.312290957  -0.013967013
H        0.124960907  -0.022012847   0.122883862
B       -0.005259620  -0.145596712  -0.040564862
H        0.199830030  -0.176142715  -0.150841828
H       -0.217291388  -0.312290957   0.013967013
H       -0.124960907   0.022012847  -0.122883862
B        0.494739818   0.354404554   0.540568678
H        0.699828966   0.323861788   0.650847745
H        0.282707973   0.187708799   0.486039576
H        0.375038882   0.522017144   0.622882523
B        0.505260182   0.645595446   0.459431322
H        0.300171034   0.676138212   0.349152255
H        0.717292027   0.812291201   0.513960424
H        0.624961118   0.477982856   0.377117477
K_POINTS automatic
 8 8 8  0 0 0


-- 
Amin Torabi
Ph.D. Student
Chemistry Department
The University *of* Western Ontario
London, On Canada, N6A 5B7
Phone: 519-661-2111 Ext: 87871
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