[Pw_forum] Iron surface Molecular Dynamics

[Vincenzo Verdolino]

Dear Giuseppe,

Thanks for your enail. I've actually optimized several iron surfaces and settings in pw.x but moving on cp.x  and ensamble-DFT I had to change many things such as pseudopotential (here i need a GC PP). If this is important I can paste here one of the pw.x relaxation input file. I did also managed to to spinpolarized finding ferromagnetic fundamental state. I agree the other option would be BO MD but I am wondering if that is not gonna take forever...plus i would eventualy scale up fron 50 atoms to a slab as big as 200

Vincenzo

Sent from my iPhone

On 08/mag/2013, at 17:36, Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it> wrote:

> 
> Dear Vincenzo
> Before discussing your setup, I note that you are using the ensemble-DFT approach implemented in cp.x. I suspect (but perhaps I may be wrong), that it 
> cannot be used to propagate ions in a proper (NVT, NPT, ...) molecular dynamics simulation, but only to optimize structures through damped molecular 
> dynamics. Have you tried first to optimize your system by using pw.x instead of cp.x, and some smearing scheme to deal with metallic systems? You could 
> eventually consider (especially if there are no H atoms involved) a Born-Oppenheimer MD with pw.x as a good solution...
> HTH
> Giuseppe
> 
> On Wednesday 08 May 2013 16:00:01 Vincenzo Verdolino wrote:
>> Dear all,
>> 
>> I am dealing with Iron surface catalyst and I'm trying to run MD simulation
>> with cp.x
>> 
>> Here is My Input file
>> 
>> &control
>>    pseudo_dir = '/cluster/home/chab/verdoliv/espresso/pseudo/',
>>    outdir='/cluster/work/scr1/verdoliv/Initial_wavefunction_min/output'
>>    prefix='Initial_wavefunction_min',
>>    title=Initial_wavefunction_min,
>>    calculation='cp',
>>    restart_mode = 'from_scratch',
>>    nstep  = 50,
>>    iprint = 10,
>>    isave  = 100,
>>    tstress = .FALSE.,
>>    tprnfor = .TRUE.,
>>    dt    = 4.0d0,
>>    etot_conv_thr = 1.d-9,
>>    ekin_conv_thr = 1.d-4,
>>    ndr = 50
>>    ndw = 51,
>> /
>> &system
>>    ibrav=  8,
>>    C=38.9305, A=7.02146, B=8.10768, cosAB=0.0, cosAC=0.0, cosBC=0.0,
>>    nat= 50,
>>    ntyp= 2,
>>    ecutwfc = 80.0, ecutrho = 640.0,
>>    smearing='cs',
>>    occupations='ensemble',
>>    nbnd = 550,
>>    nspin=1,
>>    nr1b=24, nr2b=24, nr3b=24,
>> /
>> &electrons
>>             orthogonalization = 'ortho',
>>             startingwfc = 'random',
>>             electron_dynamics = 'sd',
>>             ampre = 0.02,
>>             tcg = .true.,
>>             passop= 0.3,
>>             maxiter = 250,
>>             emass = 300,
>>             emass_cutoff = 3.00,
>>             conv_thr=1.d-6
>>             n_inner = 2,
>>             lambda_cold = 0.03,
>>             niter_cold_restart = 2,
>> /
>> &IONS
>>  ion_dynamics = 'none',
>>  ion_temperature = 'not_controlled',
>> /
>> ATOMIC_SPECIES
>> ATOMIC_SPECIES
>> Fe  1.  Fe.pw91-sp-van_ak.UPF
>> N   1.  N.pw91-van_ak.UPF
>> ATOMIC_POSITIONS angstrom
>> Fe      3.517670906   2.029585846   0.473063369
>> Fe      3.517670906   6.078055744   0.473063369
>> Fe      0.010178272   0.000000000   0.479139716
>> Fe      0.010074125   4.053800000   0.476810499
>> Fe      4.689525652   0.000000000   1.143911287
>> Fe      4.690724988   4.053800000   1.146913875
>> Fe      1.178101394   2.026148930   1.147504081
>> Fe      1.178101394   6.081492660   1.147504081
>> ...
>> ...
>> N        2.348065911   4.053800000  10.444508962
>> N        2.349799703   4.053800000  11.564212110
>> 
>> ---------------------------------------------------------------------------
>> -
>> 
>> The output file says
>> 
>> 
>> PERFORMING CONJUGATE GRADIENT MINIMIZATION OF EL. STATES
>> cg_sub: missed minimum, case 3, iteration           2
>> cg_sub: missed minimum, case 3, iteration           3
>> cg_sub: missed minimum, case 1, iteration           5
>> cg_sub: missed minimum, case 1, iteration           8
>> cg_sub: missed minimum, case 1, iteration          10
>> cg_sub: missed minimum, case 1, iteration          11
>> cg_sub: missed minimum, case 1, iteration          13
>> cg_sub: missed minimum, case 1, iteration          14
>> cg_sub: missed minimum, case 1, iteration          16
>> cg_sub: missed minimum, case 1, iteration          18
>> cg_sub: missed minimum, case 1, iteration          20
>> cg_sub: missed minimum, case 1, iteration          22
>> cg_sub: missed minimum, case 1, iteration          23
>> cg_sub: missed minimum, case 1, iteration          25
>> cg_sub: missed minimum, case 1, iteration          27
>> cg_sub: missed minimum, case 1, iteration          28
>> cg_sub: missed minimum, case 1, iteration          30
>> cg_sub: missed minimum, case 1, iteration          32
>> cg_sub: missed minimum, case 1, iteration          34
>> 
>> 
>> Could any of you give my hints on this field?
>> 
>> Thanks in advance
>> 
>> Vincenzo
> 
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>   Giuseppe Mattioli                            
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