Thanks very much. Both cases I will try with and without saturation.
________________________________
发件人: users <[email protected]> 代表 Giuseppe Mattioli 
<[email protected]>
发送时间: 2018年12月19日 21:11
收件人: [email protected]
主题: Re: [QE-users] 答复: DFT+U can not converge


Yes, I suppose so, but it is not easy to say exactly how it has to be
done in this case (H or OH saturation? surface reconstruction?). If
you are lucky, you may find something in literature...
Best
Giuseppe

LEUNG Clarence <[email protected]> ha scritto:

> Dear Giuseppe,
>
> Thanks for your suggest.
>
> My structure is (3 1 0) surface of Co3(PO4)2 with 15 angstrom
> vacuum. You mean that the unsaturated bond should be passivated by H
> or something?
>
> LIANG Xiongyi
> ________________________________
> 发件人: users <[email protected]> 代表 Giuseppe
> Mattioli <[email protected]>
> 发送时间: 2018年12月19日 19:30
> 收件人: [email protected]
> 主题: Re: [QE-users] DFT+U can not converge
>
>
> Dear Liang Xiongyi
>
> In my opinion, your initial structure is possibly wrong or missing
> necessary saturation (i.e. twofold-coordinated P atoms on the surface
> and P=O free terminations, which are likely unstable in gas phase).
> However, and generally speaking, if your calculation is going
> somewhere not so far from convergence, you can overcome a difficult
> initial step by using this very useful switch:
>
>      scf_must_converge=.false.
>
> Coupled with a suitable electron_maxstep variable, it will calculate
> forces and move atoms when scf ends. If the structure is meaningful
> and not wrong (and this may not be the case) in a few steps you should
> recover an acceptably smooth convergence.
> HTH
> Giuseppe
>
> LEUNG Clarence <[email protected]> ha scritto:
>
>> Dear QEusers,
>>
>> When I use QE6.3 to perform DFT+U to relax a slab, it is very
>> difficult to converge and even can not converge (more than 300 scf
>> steps). Thanks for your suggestion in advances.
>>
>> The input file is:
>>
>> &CONTROL
>>   calculation='relax',
>>   nstep = 200 ,
>>   wf_collect = .true. ,
>>   etot_conv_thr = 3.5D-6 ,
>>   forc_conv_thr = 4.0D-4,
>> /
>>
>> &SYSTEM
>>   ibrav=0,
>>   celldm(1)=9.6431795847d0,
>>   nat=109,
>>   ntyp=3,
>>   ecutwfc=60,
>>   ecutrho=480,
>>   input_dft='PBE',
>>   occupations='smearing',
>>   smearing = 'gaussian' ,
>>   degauss = 0.01 ,
>>   nspin = 2 ,
>>   starting_magnetization(1) = 0.5 ,
>>   lda_plus_u = .true. ,
>>   Hubbard_U(1) = 3.32 ,
>>   vdw_corr = dft-d3 ,
>> /
>> &ELECTRONS
>>   conv_thr=1d-05,
>>   mixing_beta=0.3d0,
>>   mixing_mode ='local-TF',
>>   electron_maxstep = 600 ,
>> /
>> &IONS
>> /
>> &CELL
>> /
>>
>> ATOMIC_SPECIES
>>   Co 58.933200d0 Co.pbe-spn-rrkjus_psl.0.3.1.UPF
>>   O 15.999400d0 O.pbe-n-rrkjus_psl.1.0.0.UPF
>>   P 30.973800d0 P.pbe-n-rrkjus_psl.1.0.0.UPF
>>
>> ATOMIC_POSITIONS {crystal}
>> O        0.175510868   0.823201091   0.004041902    0   0   0
>> Co       0.752963028   0.655948399   0.004313566    0   0   0
>> O        0.301125723   0.416151961   0.004879997    0   0   0
>> Co       0.846799898   0.775755648   0.005275182    0   0   0
>> Co       0.346800351   0.275755641   0.005275204    0   0   0
>> O        0.392474471   0.135359341   0.005670234    0   0   0
>> Co       0.940637166   0.895562903   0.006236666    0   0   0
>> O        0.518089326   0.728310212   0.006508330    0   0   0
>> O        0.902313840   0.059368885   0.017959393    0   0   0
>> O        0.807187857   0.964594997   0.020457557    0   0   0
>> O        0.036878250   0.705581722   0.023890599    0   0   0
>> P        0.893919682   0.538810250   0.026242849    0   0   0
>> Co       0.451343782   0.481124665   0.033750041    0   0   0
>> O        0.028914218   0.314809876   0.034323347    0   0   0
>> P        0.323165643   0.700374526   0.044655886    0   0   0
>> O        0.412931350   0.644218586   0.045243797    0   0   0
>> O        0.180081232   0.532598515   0.046685149    0   0   0
>> O        0.551818853   0.324973894   0.062282695    0   0   0
>> O        0.318968869   0.213353805   0.063724007    0   0   0
>> P        0.408734429   0.157197863   0.064311920    0   0   0
>> O        0.702985853   0.542762514   0.074644459    0   0   0
>> Co       0.280556437   0.376447725   0.075217763    0   0   0
>> P        0.837980537   0.318762141   0.082724954    0   0   0
>> O        0.695021832   0.151990660   0.085077236    0   0   0
>> O        0.924712372   0.892977386   0.088510276    0   0   0
>> O        0.829586379   0.798203506   0.091008410    0   0   0
>> O        0.213810893   0.129262179   0.102459474    0   0   0
>> Co       0.791263053   0.962009487   0.102731138    0   0   0
>> O        0.339425748   0.722213050   0.103297569    0   0   0
>> Co       0.885099923   0.081816736   0.103692754    0   0   0
>> Co       0.385100377   0.581816730   0.103692776    0   0   0
>> O        0.430774496   0.441420429   0.104087807    0   0   0
>> Co       0.978937191   0.201623991   0.104654238    0   0   0
>> O        0.556389351   0.034371300   0.104925902    0   0   0
>> O        0.940613865   0.365429972   0.116376965    0   0   0
>> O        0.845487883   0.270656085   0.118875129    0   0   0
>> O        0.075178275   0.011642810   0.122308171    0   0   0
>> P        0.932219708   0.844871338   0.124660421    0   0   0
>> Co       0.489643808   0.787185753   0.132167613    0   0   0
>> O        0.067214244   0.620870964   0.132740919    0   0   0
>> P        0.361354279   0.006083789   0.142115621
>> O        0.446802131   0.950135511   0.145110715
>> O        0.214381915   0.837791409   0.146887224
>> O        0.593110221   0.629859448   0.161855388
>> O        0.355569602   0.519337757   0.162613913
>> P        0.444333889   0.463046511   0.162481449
>> O        0.733915313   0.849462282   0.171314557
>> Co       0.331397450   0.684149370   0.174777754
>> P        0.880835007   0.624048906   0.181575275
>> O        0.729016571   0.457586972   0.184340848
>> O        0.943694570   0.199413194   0.185888622
>> O        0.842699539   0.103890146   0.188690045
>> O        0.246376254   0.435621465   0.201025875
>> Co       0.819907469   0.267437250   0.200281311
>> O        0.371654672   0.028624679   0.201597106
>> Co       0.919293748   0.386217687   0.198228118
>> Co       0.408991643   0.881622266   0.208931455
>> O        0.502982285   0.747275057   0.201700410
>> Co       0.015942502   0.506736170   0.203798000
>> O        0.581988259   0.338815157   0.205761317
>> O        0.989082264   0.670263393   0.214923633
>> O        0.891588821   0.575388161   0.217463006
>> O        0.102116329   0.316952504   0.225311380
>> P        0.946018990   0.150667428   0.220957196
>> Co       0.509889754   0.092572883   0.231027714
>> O        0.087929910   0.910622245   0.254736182
>> P        0.390071467   0.310008795   0.243522265
>> O        0.475452219   0.253683339   0.241349488
>> O        0.235229551   0.143749020   0.238654386
>> O        0.612387032   0.940393783   0.254302766
>> O        0.441611912   0.824444770   0.264038723
>> P        0.540200975   0.770461487   0.260363655
>> O        0.761099937   0.156388759   0.269996408
>> Co       0.350068981   0.991380761   0.270128489
>> P        0.873321153   0.936340371   0.286294166
>> O        0.833246668   0.765227606   0.276230271
>> O       -0.000361722   0.500532992   0.288698932
>> O        0.881119075   0.405321157   0.282221320
>> O        0.360000301   0.737045056   0.298351129
>> Co       0.882972312   0.575549749   0.299644501
>> O        0.422605865   0.327653597   0.304586136
>> Co       0.978817281   0.686215697   0.299070830
>> Co       0.413208161   0.191270814   0.293687127
>> O        0.508789991   0.058470538   0.306778792
>> Co       0.104885226   0.777001345   0.337018699
>> O        0.655258778   0.642479617   0.299146914
>> O       -0.013826595   0.991404406   0.298780328
>> O        0.795664337   0.914010571   0.342626007
>> O        0.182057906   0.620327437   0.315087245
>> P       -0.025531312   0.449691921   0.318993246
>> Co       0.536676633   0.394337417   0.322803232
>> O        0.111523355   0.238614584   0.330445421
>> P        0.458259125   0.623697091   0.344422574
>> O        0.563543106   0.565239764   0.345713118
>> O        0.245933114   0.438564927   0.345886633
>> O        0.755827316   0.261536514   0.398125722
>> O        0.347085887   0.142061029   0.350995120
>> P        0.418798485   0.087516712   0.363471914
>> O        0.760091719   0.450332386   0.364446953
>> Co       0.425302156   0.268828519   0.364933404
>> P        1.000978059   0.228830728   0.389926937
>> O        0.665322447   0.083338404   0.398947262
>> O        0.175348426   0.819170270   0.393432843
>> O        0.972375724   0.715594688   0.364967608
>> O        0.192491280   0.055768375   0.386972733
>> Co       0.947698792   0.864533921   0.380242742
>> O        0.461116896   0.646777652   0.398656956
>> Co      -0.128695091   0.044030025   0.349922760
>> Co       0.459662371   0.500794114   0.364054027
>>
>>
>> K_POINTS {automatic}
>>   3 3 1 0 0 0
>>
>> CELL_PARAMETERS {alat}
>>   1.000000000000d0  0.000000000000d0  0.000000000000d0
>>   -0.125138500246d0  5.222389311845d0  0.000000000000d0
>>   0.000000000000d0  0.000000000000d0  4.847983163860d0
>>
>> LIANG Xiongyi
>> CIty University of Hong Kong
>
>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> Via Salaria Km 29,300 - C.P. 10
> I-00015 - Monterotondo Scalo (RM)
> Mob (*preferred*) +39 373 7305625
> Tel + 39 06 90672342 - Fax +39 06 90672316
> E-mail: <[email protected]>
>
> _______________________________________________
> users mailing list
> [email protected]
> https://lists.quantum-espresso.org/mailman/listinfo/users



GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <[email protected]>

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