[Pw_forum] Reply to Paolo Cazzato

aaron at nemo.physics.ncsu.edu aaron at nemo.physics.ncsu.edu
Wed Dec 8 15:43:13 CET 2004


Hi Tim,

I am not the FPMD expert but maybe you would like to see my suggestions:

First make the number of steps in your electronic minimization equal to 
the isave value, so that restart files can be written.  These will include 
your optimized electronic wavefunction.

Next if you set your ion_dynamics to 'none', the ions will not move.

Now somewhere in the output you will see a value of electronic kinetic
energy ("ekinc" maybe).  If the minimization proceeded correctly this will 
diminish to approximately zero.  

Now you have a restart file from which you can start a job to update the
ionic positions.

Good luck

Aaron

 On Wed, 8 Dec 2004, Timothy A.V. 
Teatro wrote:

> Thank you very much for your replay. I somehow missed it, and this is why it
> has taken my so long to respond. You are correct that I did not run any
> electronic minimization. I am only familiar with PWscf, which seems to deal
> with this automatically when one desires only dynamics.
> 
> I'm not quite sure how to do an electronic minimization (I'm just barely a
> second year physics undergrad, so I am quite new to this stuff). Would you
> mind giving me an example? Perhaps even, if you still have your input file
> from which you ran my calculation?
> 
> I'm really sorry to ask such things of you sir, but it would help me out a
> tremendous amount.
> 
> Once again, thank you very much!
> 
> In case you need my input file again:
> 
> #!/bin/sh
> 
> PW_ROOT=$HOME/cpmd/FPMD
> PSEUDO=$HOME/cpmd/pseudo
> TMP_DIR=$HOME/cpmd/tmp0
> 
> if [ ! -d results ]; then 
>    mkdir  results
> fi
> cd results
> 
> rm -rf $TMP_DIR/*
> 
> cat > sih.cp1.in << EOF
> 
> &CONTROL
>   title = ' Silicon ',
>   calculation = 'cp',
>   restart_mode = 'from_scratch',
>   pseudo_dir = '$PSEUDO/',
>   outdir='$TMP_DIR/',
>   ndr = 51,
>   ndw = 51,
>   nstep  = 50,
>   iprint = 10, 
>   isave  = 100,
>   tstress = .TRUE.,
>   tprnfor = .TRUE.,
>   dt    = 5.0d0,
>   etot_conv_thr = 1.d-9,
>   ekin_conv_thr = 1.d-4,
>   prefix = 'si'
> /
> 
> &SYSTEM
>   ibrav = 1, 
>   celldm = 10.61,
>   nat  = 2,
>   ntyp = 1,
>   nbnd = 4,
>   nelec = 8,
>   ecutwfc = 8.0,
>   xc_type = 'BLYP'
> /
> 
> &ELECTRONS
>   emass = 400.d0,
>   emass_cutoff = 2.5d0,
>   orthogonalization = 'ortho',
>   ortho_eps = 5.d-8,
>   ortho_max = 15,
>   electron_dynamics = 'sd',
>   ! electron_damping = 0.3,
>   electron_velocities = 'zero',
>   electron_temperature = 'not_controlled',
> /
> 
> &IONS
>   ion_dynamics = 'verlet',
>   ion_damping = 0.2,
>   ion_radius(1) = 0.8d0,
>   ion_radius(2) = 0.8d0,
>   ion_velocities = 'zero',
>   ion_temperature = 'nose',
>   tempw = 1000,
>   fnosep = 1.2,
>   tolp=100,
>   ion_nstepe = 10
> /
> 
> &CELL
>   cell_dynamics = 'pr',
>   cell_velocities = 'zero',
>   press = 0.0d0,
> /
> 
> ATOMIC_SPECIES
>  Si  28.086  Si.vbc.UPF 4
> 
> ATOMIC_POSITIONS
> Si 0.00 0.00 0.00
> Si 0.00 0.00 0.10
> 
> K_POINTS
>  1
>  0.0 0.0 0.0 1.0
> EOF
> 
> $PW_ROOT/par2.x < sih.cp1.in > Si.md64H.out
> 
> 
> 
> 
> -----------------------------------------------------------------------
> Dear Timothy,  are you sure that you are following the manual in your fpmd
> calculation:
>     The first run, when starting from scratch, is always an electronic
>     minimization, with fixed ions and cell, to bring the electronic
>     system on the ground state (GS) relative to the starting atomic
>     configuration.
> 
> I'm using the current version of espresso and, running your job after the
> electronic minimization, atoms move at least.
> 
> Paolo Cazzato
> 
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