The ABINIT Users Mailing List ( CLOSED )

[Emmanuel Arras <emmanuel.arras@cea.fr>]

you can use

pawovlp -1

(http://www.abinit.org/documentation/helpfiles/for-v5.8/input_variables/varpaw.html#pawovlp)

and see if for the final positions, the paw spheres are still overlapping :
- if they don't, then it's ok, your calculation is fine. you don't need 
to do anything.
- if they still do, you should regenerate paw dataset with smaller radii.

anyway changing the supercell geometry won't change anything.


(By the way, your xred positions for z coordinates look quite strange, 
but it is no real problème.)



chengdaojian@gmail.com a écrit :
> Dear All Users,
>
> I have a problem with "PAW SPHERES ARE OVERLAPPING!". It happens only in the
> beginning of the SCF cycle, because some atoms have moved a lot randomly. So:
> 1) Should I make make PAW data sets with radii small enough that they do not
> overlap?  Can this action work when the atoms move a lot in the beginning of
> the SCF cycle?
> 2) Should I use a supercell geometry or other ionmov setting? Here I used only
> one atom per layer and ionmov = 3.
>
> The ERROR:
>  Cartesian coordinates (bohr)
>   0.00000000000000E+00  0.00000000000000E+00  0.00000000000000E+00
>  -2.35349888466629E-08  2.71758625030793E+00  3.84324748168752E+00
>   2.35349887474799E+00  1.35879310477207E+00  7.68649496337505E+00
>   6.36427513530181E-04 -3.64574119790697E-04  1.15316906583828E+01
>   5.35980233565532E-02  2.68663712421063E+00  1.54673211838139E+01
>  -2.18889392228279E-02	1.26325808216285E-02  1.89255486877382E+01 
>  fconv : at Broyd/MD step   2, gradients have not converged yet.
>   max grad (force/stress) = 4.2691E-02 > tolmxf= 5.0000E-04 ha/bohr (free
> atoms)
>  BROYDEN STEP NUMBER   3 
> ------------------------------------------------------ 
>  findmin : WARNING -
>   The 2nd degree equation has no positive root (choice=4). 
>  findmin : COMMENT -
>   Will continue, since the new total energy is lower
>   than the old. Take a larger step in the same direction.
>    line minimization, algorithm   4
>                         lambda      etotal            dedv        d2edv2
>    old point         :  0.0000E+00 -2.0458222678E+02 -4.4545E-03  5.4768-315
>    new point         :  1.0000E+00 -2.0458657309E+02 -4.3814E-03  2.0072E+10
>    predicted point   :	2.5000E+00 -2.0459268701E+02  0.0000E+00  6.7989-259 
>  Cartesian coordinates (bohr)
>   0.00000000000000E+00  0.00000000000000E+00  0.00000000000000E+00
>  -2.35349888466629E-08  2.71758625030793E+00  3.84324748168752E+00
>   2.35349887474799E+00  1.35879310477207E+00  7.68649496337505E+00
>   2.22720503993542E-02 -1.27882177834460E-02  1.15514582429084E+01
>   1.56557949979702E+00  1.81359878370057E+00  1.41769829818673E+01
>  -6.43183869046093E-01  3.71215698548800E-01  2.02198822354872E+01
>      iter   Etot(hartree)     deltaE(h) residm	  nres2    magn 
>  FFT (fine) grid used in SCF cycle: 
>  getcut: wavevector=  0.0000  0.0000  0.0000  ngfft=  30  30 225
> 	 ecut(hartree)=     50.000   => boxcut(ratio)=	 2.00377 
>  chkpawovlp : ERROR -
>   PAW SPHERES ARE OVERLAPPING !
>    Distance between atoms   4 and   5 is  :   3.55118
>    PAW radius of the sphere around atom   4 is:   2.31080
>    PAW radius of the sphere around atom   5 is:   2.31080
>    This leads to a (voluminal) overlap ratio of  7.43 %
>
> Another ERROR:
>  chkpawovlp : ERROR -
>   PAW SPHERES ARE OVERLAPPING !
>    Distance between atoms   5 and   6 is  :   3.04748
>    PAW radius of the sphere around atom   5 is:   2.31080
>    PAW radius of the sphere around atom   6 is:   1.11202
>    This leads to a (voluminal) overlap ratio of  5.43 %
>
> My input: t11.in
> rprim
>    .70710678  .0000000  .000000
>  -0.35355339 0.6123724  .000000
>    .000000    .000000  5.1961524 
> occopt 7 tsmear 0.01  kptopt 1	
> ntypat 2    
> znucl 28 6   
> ngkpt  4 4 1
> nshiftk 1
> shiftk	0.5 0.5 0.5 
> acell 3*6.6567
> #chkprim = 0 
> natom 6  
> typat 1 1 1 1 1 2  
> xred
>    .00000000   .00000000   .00000000
>    .33333333   .66666667   .11111111
>    .66666667   .33333333   .22222222
>    .00000000   .00000000   .33333333
>    .33333333   .66666666   .44444444
>    .00000000   .00000000   .55000000 
> natfix 3
> iatfix 1 2 3 
> ionmov 3
> tolmxf 5.0d-4
> ntime 200 
> ixc 11	 
> ecut 26 
> nsppol 2
> spinat 0.0 0.0 0.5
>        0.0 0.0 0.5
>        0.0 0.0 0.5
>        0.0 0.0 0.5
>        0.0 0.0 0.5
>        0.0 0.0 0
> pawecutdg 50.
> getwfk -1
> prteig 0 prtden 0
> optforces 2
> diemac  100
> diemix  0.2
> nline  16
> npulayit  30
> nstep  200
> toldfe 1.0d-6
>
> My input: t1x.files
> t11.in
> t1x.out
> t1xi
> t1xo
> t1x
> ../../Psps_for_tests/Ni.atompaw.gga.paw
> ../../Psps_for_tests/C-GGA-hard.paw
>
>   

--
Emmanuel ARRAS
L_Sim (Laboratoire de Simulation Atomistique)
SP2M / INAC
CEA Grenoble
tel : 00 33 (0)4 387 86862