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
Scrive "Timothy A.V. Teatro" <tim_teatro at rogers.com>:
> Hi. I'm really sorry to ask a question like this. I wrote this input
> file a while ago. I have been fiddling with it for a while now, and I
> can't figure out why I can't get two simple little silicon atoms to
> move! I am accustomed to using PWscf, but I am not trying to switch to
> FPMD for more accurate dynamics. But I cannot get any dynamics out of
> this thing! Even when I try putting the Si atoms very close to each
> other, where the forces should be enormous I can't get them to move.
>
> Thanks a lot for looking at this. I'm sure I did something very silly,
> which is going to embarrass me later.
>
> Here is a verbatim listing of the input script:
>
> #!/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
>
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