[QE-users] Wrong prediction for Pd-Pd bond length

pboulet pascal.boulet at univ-amu.fr
Tue Jan 29 10:03:24 CET 2019


It looks ok for a cluster of this size, but I am not an expert in nanoparticles, except for spin polarization: if Pd85 is diamagnetic I would expect neither spin nor starting_magnetization  keywords. You will have to run tests to check convergence with ecutrho and ecutwfc. Nobody can help you with this.


Best, 

Pascal Boulet
—
Professor in computational chemistry - DEPARTMENT OF CHEMISTRY
Director of the Madirel laboratory
Aix-Marseille University - Avenue Escadrille Normandie Niemen - F-13013 Marseille - FRANCE
Tél: +33(0)4 13 55 18 19 - Fax : +33(0)4 13 55 18 50
Email : pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>




> Le 29 janv. 2019 à 03:08, Paolo Costa <paolo.costa85 at gmail.com> a écrit :
> 
> Dear Pascal,
> 
> thanks a lot for your detailed answer. 
> I have a doubt regarding the occupation. You suggested me to change from smearing to fixed. Why? 
> Moreover, the Pd dimer is just a starting point since I have to calculate a larger cluster of Pd (e.g. Pd85). I need to compute adsoprtion energies of organic substrate on Pd85 cluster. 
> I read in lit. (J. Phys. Chem. A 2008, 112, 8911–8915) that Pd85 is a diamagnetic cluster, thus I will not run any spin-polarization calculation. 
> Do you have any advise for me on running efficiently such 'heavy' calculation? the following is the input file I prepared. 
> 
> Thanks.
> 
> &CONTROL
>      calculation   = "relax"
>    prefix ='PdNP85'
>     forc_conv_thr =  1.0e-04
>     max_seconds   =  1.0e+14
>     nstep         = 800
>     pseudo_dir    = "/home/pcosta/pseudo"
> 	verbosity     ='high'
>    disk_io ='none'
>     tprnfor       = .TRUE.
>     tstress       = .TRUE.
> /
> 
> &SYSTEM
>     a     =  3.50000e+01
>     degauss                   =  1.50000e-02
>     ecutrho                   =  1.84000e+02
>     ecutwfc                   =  1.8400e+01
>     lda_plus_u                = .FALSE.
>     ibrav                     = 1
>     nat                       = 85
>     nspin                     = 1
>     ntyp                      = 1
>     occupations               = "smearing"
>     smearing                  = "gaussian"
>     starting_magnetization(1) =  2.00000e-01
>     vdw_corr                  = 'grimme-d3'
> /
> 
> &ELECTRONS
>     conv_thr         =  1.00000e-08
>     diagonalization  = "david"
>     diago_david_ndim=2
>     mixing_ndim = 4
>     electron_maxstep = 800
>     startingpot      = "atomic"
>     startingwfc      = "atomic+random"
> /
> 
> &IONS
>     ion_dynamics = "bfgs"
> 	trust_radius_min=1e-5
> /
> 
> K_POINTS {gamma}
> 
> ATOMIC_SPECIES
> Pd    106.42000  Pd.pbe-n-kjpaw_psl.1.0.0.UPF
> 
> ATOMIC_POSITIONS {angstrom}
> Pd     15.776820  15.903080  18.073770
> Pd     13.861740  15.947890  16.372170
> Pd     15.426330  16.891080  14.607090
> Pd     17.339080  16.844820  16.311460
> Pd     18.903660  17.788010  14.546390
> Pd     19.237700  16.790950  18.028860
> Pd     20.816440  17.748340  16.229570
> Pd     17.689590  15.856780  19.778310
> Pd     16.975260  17.828530  12.847760
> Pd     18.570070  18.796940  11.026040
> Pd     20.500000  18.751390  12.742100
> Pd     22.364760  18.706220  14.403920
> Pd     19.600740  15.810070  21.482820
> Pd     21.206620  16.763870  19.717150
> Pd     22.748800  17.737590  17.835530
> Pd     24.322110  18.688150  16.053790
> Pd     11.886050  15.964270  14.712830
> Pd     13.491300  16.916240  12.952550
> Pd     15.004030  17.840610  11.205900
> Pd     16.545790  18.780840   9.431780
> Pd     10.275990  14.989220  16.543560
> Pd     12.269750  14.998870  18.133740
> Pd     14.170130  14.930450  19.899420
> Pd     16.138350  14.920080  21.533320
> Pd     18.056230  14.884320  23.208070
> Pd     14.812290  19.063690  13.385100
> Pd     16.379960  20.041440  11.613080
> Pd     18.303760  20.017670  13.301860
> Pd     16.728710  19.035300  15.082270
> Pd     18.648070  19.012670  16.763720
> Pd     15.156510  18.054700  16.859480
> Pd     17.076040  18.034690  18.532810
> Pd     13.234570  18.083640  15.155940
> Pd     20.227600  19.993890  14.990690
> Pd     22.151300  19.970120  16.679380
> Pd     20.570710  18.988560  18.452590
> Pd     18.987980  18.008990  20.217740
> Pd     11.679690  17.105560  16.939740
> Pd     13.591300  17.086050  18.604820
> Pd     15.497560  17.050130  20.317280
> Pd     17.401810  17.014340  22.027600
> Pd     14.353250  13.784050  17.521250
> Pd     12.421840  13.836590  15.841810
> Pd     13.994670  14.793240  14.062880
> Pd     15.935220  14.740470  15.750230
> Pd     17.500910  15.694120  13.975160
> Pd     17.872280  14.687800  17.434540
> Pd     19.429680  15.639620  15.658700
> Pd     16.284240  13.728290  19.210540
> Pd     15.567540  15.749910  12.283910
> Pd     17.140290  16.706510  10.505080
> Pd     19.073920  16.650450  12.197390
> Pd     20.999510  16.591890  13.891230
> Pd     18.226670  13.682240  20.878200
> Pd     19.776270  14.629820  19.109600
> Pd     21.374640  15.586780  17.349740
> Pd     22.970990  16.542650  15.591720
> Pd     17.813280  14.564160  11.809350
> Pd     16.272540  13.570020  13.595860
> Pd     14.725500  12.579240  15.366950
> Pd     18.215930  13.541560  15.273450
> Pd     16.666980  12.552890  17.036500
> Pd     19.760790  14.538960  13.480320
> Pd     21.688380  14.503850  15.165370
> Pd     20.145540  13.519610  16.919810
> Pd     18.618160  12.524270  18.720940
> Pd     12.824840  19.253220  17.422890
> Pd     14.389300  20.188650  15.625310
> Pd     15.937510  21.120970  13.823770
> Pd     16.330060  20.205960  17.306090
> Pd     17.870000  21.136320  15.503860
> Pd     14.759580  19.267480  19.108760
> Pd     16.705570  19.291080  20.772730
> Pd     18.237800  20.217270  18.977850
> Pd     19.818670  21.153740  17.191370
> Pd     18.518490  12.413770  12.842670
> Pd     16.923030  11.449920  14.609650
> Pd     18.863830  11.377970  16.278280
> Pd     20.420780  12.330080  14.518590
> Pd     15.802800  22.375450  16.028650
> Pd     14.249000  21.410550  17.831820
> Pd     16.203800  21.434420  19.485420
> Pd     17.719490  22.386670  17.690140
> Pd     15.573820  23.543960  18.485200
> Pd     19.033400  10.228370  14.054610
> 
> 
> Il giorno lun 28 gen 2019 alle ore 11:31 pboulet <pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>> ha scritto:
> As a supplement to Giuseppe’s and Lorenzo's comments:
> 
> 1- forc_conv_thr should be smaller: about 1e-4 or 1e-5 (why using 1.94469e-03 with that many digits?)
> 2- add: etot_conv_thr= 1e-7
> 2- I would use ibrav=0 together with CELL-PARAMETERS (see online manual)
> 3- occupation=fixed, no smearing, and nbnd=number of occupied states+ a few virtual ones. It should work as you have a dimer.
> 4- why using vdW corrections? not sure they are significant. Furthermore, as a remember Grimme’s corrections are not that good for metals. I got too large bond distances for gold (but it was for a solid)… 
> 5- mixing_beta=0.2 should do the job and you eventually avoid oscillations in the SCF convergence if you use a too large value (or even no convergence at all).
> 6- &CELL … / section is not necessary as you only optimise atomic positions.
> 7- K_POINTS {Gamma} is all right as you have a molecule (k-points are only meaningful for slabs and bulk structures)
> 
> HTH,
> Best
> 
> 
> Pascal Boulet
>> Professor in computational chemistry - DEPARTMENT OF CHEMISTRY
> Director of the Madirel laboratory
> Aix-Marseille University - Avenue Escadrille Normandie Niemen - F-13013 Marseille - FRANCE
> Tél: +33(0)4 13 55 18 19 - Fax : +33(0)4 13 55 18 50
> Email : pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>
> 
> 
> 
> 
>> Le 28 janv. 2019 à 16:44, Paolo Costa <paolo.costa85 at gmail.com <mailto:paolo.costa85 at gmail.com>> a écrit :
>> 
>> Dear QE users,
>> 
>> I am trying to optimize (relax) Pd dimer (Pd2) as cluster placed on cubic lattice.
>> However I got a value of Pd-Pd bond length which is far too long (3.36 A) compare to the experimental one (about 2.6 A).
>> Am I doing something wrong? Here below the input file:
>> 
>> &CONTROL
>>      calculation   = "relax"
>> prefix ='Pd2'
>>     forc_conv_thr =  1.94469e-03
>>     max_seconds   =  1.34369e+14
>>     nstep         = 800
>>     pseudo_dir    = "/home/pcosta/pseudo"
>> 	verbosity     ='high'
>> disk_io ='none'
>>     tprnfor       = .TRUE.
>>     tstress       = .TRUE.
>> /
>> 
>> &SYSTEM
>>     a     =  4.50000e+01
>>     degauss                   =  1.00000e-02
>>     ecutrho                   =  1.83747e+01
>>     ecutwfc                   =  1.46997e+00
>> 	lda_plus_u                = .FALSE.
>>     ibrav                     = 1
>>     nat                       = 2
>>     nspin                     = 2
>>     ntyp                      = 1
>>     occupations               = "smearing"
>>     smearing                  = "gaussian"
>>     starting_magnetization(1) =  2.00000e-01
>>     assume_isolated = 'makov-payne'
>> 	vdw_corr                  = 'grimme-d3'
>> /
>> 
>> &ELECTRONS
>>     conv_thr         =  1.00000e-08
>>     diagonalization  = "david"
>>     electron_maxstep = 800
>>     mixing_beta      =  4.00000e-01
>>     startingpot      = "atomic"
>>     startingwfc      = "atomic+random"
>> /
>> 
>> &IONS
>>     ion_dynamics = "bfgs"
>> 	trust_radius_min=1e-5
>> /
>> 
>> &CELL
>>     cell_dofree    = "all"
>>     cell_dynamics  = "bfgs"
>>     press_conv_thr =  5.00000e-01
>> /
>> 
>> K_POINTS {automatic}
>>  3  3  1  0 0 0
>>   
>> ATOMIC_SPECIES
>> Pd    106.42000  Pd.pbe-n-kjpaw_psl.1.0.0.UPF
>> 
>> ATOMIC_POSITIONS {angstrom}
>> Pd     16.194860  19.259990  18.659720
>> Pd     18.251640  18.665930  18.594650
>> 
>> Thanks.
>> -- 
>> Paolo Costa, Ph.D.
>> Postdoctoral Researcher
>> Department of Chemistry and Biomolecular Sciences
>> University of Ottawa
>> 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
>> Room number: DRO 326 (D'Iorio Hall)
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> 
> -- 
> Paolo Costa, Ph.D.
> Postdoctoral Researcher
> Department of Chemistry and Biomolecular Sciences
> University of Ottawa
> 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
> Room number: DRO 326 (D'Iorio Hall)
> _______________________________________________
> users mailing list
> users at lists.quantum-espresso.org
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