The ABINIT Users Mailing List ( CLOSED )

[mmikami@rc.m-kagaku.co.jp]

Hi,

One of my concerns is :
        znucl 94 8
Is there any sufficiently good pseudopotential for Pu ?
Even if it would be available, spin-orbit could treat the system well ?
 (In this input, just a normal input without spin-orbit treatment, 
though)
Other reason would be mentioned. LDA could work for Pu-compounds ? etc.

I am preparing FAQ for ABINIT now. In the beta version, I made :
Q: Why do my ABINIT results differ from experimental results ?
A: Many reasons ! your input (system/assumption, input parameters,
pseudopotentials ...) might be wrong; ABINIT might have bugs;
the present formalism in DFT(LDA/GGA etc.) could not treat your
system well... So you may post your questions to the "Forum" mailing
list (forum@abinit.org). Please describe specific/concise information
as possible as you can.

In any case,  attachment of the input would be very fine
for "forum" readers not to guess what you are doing.
(The input was really beyond my imagination ...)
I will a bit modify the above Q&A. Thanks.

Best wishes,
Masayoshi

On 2003.4.2, at 15:50 Asia/Tokyo, M.T.Storr wrote:

> Hi,
>
> In response to a recent e-mail here is my input file, I am using Abinit
> v4.0.3.
>
> Thanks
>
> Mark
>
> #Geometry Optimisation
> optcell 2    # Optimise Nuclear Positions only.
> ionmov 3     # Broyden-Fletcher-Goldfarb-Shanno minimization (BFGS).
> ntime 50     # Number of BFGS steps.
> dilatmx 2.50
> ecutsm 0.0
> prtcml 1     # Print output geometry.
>
> #Definition of the unit cell
> acell 3*7.211676784    # This is equivalent to 3.816255 X 3.816255 X 
> 3.816255
> rprim  0.0  0.5  0.5   # In lessons 1 and 2, these primitive vectors
>        0.5  0.0  0.5   # (to be scaled by acell) were 1 0 0  0 1 0  0 
> 0 1
>        0.5  0.5  0.0   # that is, the default.
>
> #Definition of the atom types
> ntype 2                # There are two types of atom.
> znucl 94 8             # The keyword "znucl" refers to the atomic 
> number of the
>                        # possible type(s) of atom. The 
> pseudopotential(s)
>                        # mentioned in the "files" file must correspond
>                        # to the type(s) of atom.
>
> #Definition of the atoms
> natom 3                # There are three atoms
> type 1 2 2
> xred                   # This keyword indicates the position of the 
> atoms is in reduced coordinates.
>    0.000000   0.000000   0.000000
>    0.250000   0.250000   0.250000
>   -0.250000  -0.250000  -0.250000
>
> #Definition of the Functional to use
> ixc 1                  # LDA or LSD, Teter Pade parametrization (4/93).
>                        # Which reproduces Perdew-Wang (which 
> reproduces Ceperley-Alder).
> nsppol 2               # Spin polarised functional.
>
> #Definition of the planewave basis set
> ecut 50.0             # Maximal kinetic energy cut-off, in Hartree
>
> #Definition of the k-point grid
> kptopt 1          # Option for the automatic generation of k points, 
> taking
>                   # into account the symmetry
> ngkpt 6 6 6       # Definition of the different grids
>
> nshiftk 4         # repeated four times, with different shifts
>
> shiftk 0.5 0.5 0.5
>        0.5 0.0 0.0
>        0.0 0.5 0.0
>        0.0 0.0 0.5
>                   # In cartesian coordinates, this grid is simple 
> cubic, and
>                   # actually corresponds to the
>                   # so-called 4x4x4 Monkhorst-Pack grid
>
> #Definition of the SCF procedure
> nstep 50               # Maximal number of SCF cycles
> diemac 9.0             # Although this is not mandatory, it is worth to
> diemix 1.0             # precondition the SCF cycle. The model 
> dielectric
>                        # function used as the standard preconditioner
>                        # is described in the "dielng" input variable 
> section.
> toldfe   1.0d-6        # Will stop when, twice in a row, the difference
>                        # between two consecutive evaluations of total 
> energy
>                        # differ by less than toldfe (in Hartree).
>                        # Only 1 value of tol.... need be specified.
>
> On Tue, 1 Apr 2003, Chris Fischer wrote:
>
> > Mark,
> >
> > Could you copy your input file along with your response. What version 
> > of
> > ABINIT are you using ?
> >
> > -Chris
> >
> > M.T.Storr wrote:
> >
> > > Riad,
> > >
> > > thanks for the suggestion, I can gte the calculation to run for one 
> > > step
> > > by increasing the dilatmx to 3.00 which I believe means allow for a 
> > > 300%
> > > increase in cell size. However the calculation then dies with the 
> > > same
> > > problem. It therefore appears that Abinit is unable to run a geometry
> > > optimisation on my 3 atoms primitive unit cell. Is this a problem 
> > > with
> > > Abinit or my input? The input structure is of course from the
> > > crystallographic database and as such should be reasonably near to 
> > > the DFT
> > > cell.
> > > Any further suggestions would be greatfully appreciated.
> > >
> > > Thanks
> > >
> > > Mark
> > >
> > > On Mon, 31 Mar 2003, Riad Shaltaf wrote:
> > >
> > >
> > >
> > > > Hi..
> > > >
> > > > I think the problem is that your cell expanded very much after the 
> > > > first
> > > > optemization step which makes the
> > > > maximum nomber of plane waves included in the calculation through 
> > > > the
> > > > value of dilatmx is not enuogh to cover the expanded cell. I think 
> > > > if you
> > > > start from larger lattice parameter or if you give larger value for
> > > > dilatmx, you may solve this problem.
> > > >
> > > > I hope this might help.
> > > > On Sun, 30 Mar 2003, M.T.Storr wrote:
> > > >
> > > >
> > > >
> > > > > Hi,
> > > > >
> > > > > thanks to those people who answered my questions on the number of 
> > > > > bands in
> > > > > a calculation. The question has now been resolved and replaced by 
> > > > > several
> > > > > further questions!
> > > > > I have run through the study of ecut, then the number of kpoints 
> > > > > for my
> > > > > system and so am now at the point of running a geometry 
> > > > > optimisation,
> > > > > however I am running into problems with ecut/boxcut.
> > > > > I have chosen an ecut of 50 Ha and a kpoint grid as follows:
> > > > >
> > > > > #Definition of the k-point grid
> > > > > kptopt 1          # Option for the automatic generation of k 
> > > > > points,
> > > > > taking
> > > > >                  # into account the symmetry
> > > > > ngkpt 6 6 6       # Definition of the different grids
> > > > >
> > > > > nshiftk 4         # repeated four times, with different shifts
> > > > >
> > > > > shiftk 0.5 0.5 0.5
> > > > >       0.5 0.0 0.0
> > > > >       0.0 0.5 0.0
> > > > >       0.0 0.0 0.5
> > > > >                  # In cartesian coordinates, this grid is simple 
> > > > > cubic, and
> > > > >                  # actually corresponds to the
> > > > >                  # so-called 4x4x4 Monkhorst-Pack grid
> > > > >
> > > > > However when I try to run the geometry optimisisation using:
> > > > >
> > > > > optcell 2    # Optimise Nuclear Positions only.
> > > > > ionmov 3     # Broyden-Fletcher-Goldfarb-Shanno minimization 
> > > > > (BFGS).
> > > > > ntime 10     # Number of BFGS steps.
> > > > > dilatmx 1.15
> > > > > ecutsm 0.0
> > > > >
> > > > > Then when the program goes through the input data and echoes the 
> > > > > dataset
> > > > > it uses and ecut of:
> > > > >
> > > > > getcut: wavevector=  0.0000  0.0000  0.0000  ngfft=  40  40  40
> > > > >         ecut(hartree)=     66.125   => boxcut(ratio)=   2.14285
> > > > >
> > > > > whihc is not the 5o Ha that I requested.
> > > > > However the program goes ahead and runs the Broyden Step 0, 
> > > > > however at the
> > > > > end of this step the program then goes to Broyden Step 1 and then 
> > > > > selects
> > > > > the Ecut as requested of 50 Ha:
> > > > >
> > > > > getcut: wavevector=  0.0000  0.0000  0.0000  ngfft=  40  40  40
> > > > >         ecut(hartree)=     50.000   => boxcut(ratio)=   0.67925
> > > > >
> > > > > However as can be seen the boxcut is now below 1 and I get the 
> > > > > following
> > > > > error:
> > > > >
> > > > > getcut: ERROR -
> > > > >  Choice of acell, ngfft, and ecut
> > > > >  ===> basis sphere extends BEYOND fft box!
> > > > >  Recall that boxcut=Gcut(box)/Gcut(sphere)  must be > 1.
> > > > >  Action : try larger ngfft or smaller ecut.
> > > > >  Note that ecut=effcut/boxcut**2 and effcut=   23.068977
> > > > >
> > > > > The question is what am I doing wrong. I would like to use an ecut 
> > > > > of 50
> > > > > Ha, and have therefore tried increasing ngfft however I tried 50 
> > > > > 50 50
> > > > > and got a boxcut(ratio)=0.84940. This suggests that I would need to
> > > > > increase ngfft to a rather large value just to get the calculation 
> > > > > to run.
> > > > > Therefore I would like to know why for the Broyden step 0 the 
> > > > > program
> > > > > appears to select its own value of ecut which when used to 
> > > > > intialise
> > > > > variables such as ngfft etc means that at step 1 when it uses the 
> > > > > correct
> > > > > value all the initialised variables are wrong. Any suggestions how 
> > > > > to
> > > > > solve this would be great.
> > > > >
> > > > > Many Thanks
> > > > >
> > > > > Mark
> > > > >
> > > > > --
> > > > > Mark T. Storr
> > > > > Research Fellow
> > > > > School of Chemistry
> > > > > University of Reading
> > > > > PO Box 224
> > > > > Whiteknights
> > > > > Reading
> > > > > Berkshire
> > > > > RG6 6AD
> > > > > Tel: +44 (0)118 9875123 Ext. 7415
> > > > > E-mail: M.T.Storr@reading.ac.uk
>
> --
> Mark T. Storr
> Research Fellow
> School of Chemistry
> University of Reading
> PO Box 224
> Whiteknights
> Reading
> Berkshire
> RG6 6AD
> Tel: +44 (0)118 9875123 Ext. 7415
> E-mail: M.T.Storr@reading.ac.uk