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Dear Amin Torabi<br>
you are performing a variable-cell MD simulation therefore the
enthalpy is not minimized by the Newton equations for atoms+cell are
integrated to give you the dynamics around the target pressure (P=0
in your case).<br>
to get the relaxation you should use calculation = "vc-relax" and
then choose the minimization strategy.<br>
the default is bfgs but also damp dynamics is available.<br>
check the relevant input variables: ion_dynamics and
cell_dynamics.<br>
<br>
best regards, <br>
stefano<br>
<br>
<br>
On 10/28/2011 02:49 AM, Amin Torabi wrote:
<blockquote
cite="mid:CAEXRF5wa4U1PzSdgSH1FLyyftZ07X-FaOGQdoLbgEdjpKM3HdQ@mail.gmail.com"
type="cite">
<pre wrap="">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
</pre>
<pre wrap="">
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</pre>
</blockquote>
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