[CPMD-list] position restraints not working

[Martin Konopka]

Dear Ari,

Thank you. I looked into setsys.F and really, the conversion of the units 
looks to be missing there for position restraints. (For some other kinds of 
restraints the conversion is implemented.) MD in my test worked correctly 
when supplying the input in A.U.; also the frequency of the osillations was 
as it should be.

I am not so sure about the geometry optimization - even setting kval to 100 
A.U.
(and setting a tough convergence criteria) does not attract the atoms into 
the restraint centers and the optimization stops somehow early. You can see 
my input file below and also a piece of the output.

I put the TESR 2 into my previous input file just by a mistake.

&CPMD
   OPTIMIZE GEOMETRY
   CONVERGENCE
     1.0D-7  1.0D-5
   CONVERGENCE CALFOR
     1.01D0
   CONVERGENCE RELAX
     20
   SPLINE POINTS QFUNCTION
     2001
&END

&DFT
   FUNCTIONAL PBE
   GC-CUTOFF
     1.0D-7
&END

&SYSTEM
   SYMMETRY
     0
   POISSON SOLVER TUCKERMAN
   CELL ABSOLUTE
     11.3383568035275  11.3383568035275  18.8972613392125    0.0  0.0  0.0
   CUTOFF
     70.0D0
&END

&ATOMS
*H-q1
   LMAX=S
    2
      5.68807566310297  5.70697292444218  14.1540487430702
      5.63138387908533  5.68807566310297   4.6865208121247
CONSTRAINTS
   RESTRAINTS
     2
     RESPOS  1   5.66917840176376  5.66917840176376  14.1729460044094    0.0 
 100.0
     RESPOS  2   5.66917840176376  5.66917840176376  4.72431533480313    0.0 
 100.0
END CONSTRAINTS
&END

****************************************************************
  *** TOTAL STEP NR.    94           GEOMETRY STEP NR.      9  ***
  *** GNMAX=  2.980845E+00 [5.86E-08]     ETOT=     -0.920301  ***
  *** GNORM=  1.798356E+00               DETOT=     7.356E-13  ***
  *** CNSTR=  0.000000E+00                TCPU=          1.88  ***
  ****************************************************************
  ================================================================
  =              END OF GEOMETRY OPTIMIZATION                    =
  ================================================================



  RESTART INFORMATION WRITTEN ON FILE                  ./RESTART.1


                      <<<<< RESTRAINTS >>>>>
  RESTRAINED STRUCTURE ELEMENTS
       TYPE     ATOM ATOM ATOM ATOM       VALUE     FORCE CONSTANT
     RESPOS        1 5.67 5.6714.17     0.00000          100.0
     RESPOS        2 5.67 5.67 4.72     0.00000          100.0


  ****************************************************************
  *                                                              *
  *                        FINAL RESULTS                         *
  *                                                              *
  ****************************************************************

    ATOM          COORDINATES            GRADIENTS (-FORCES)
    1  H  5.6960  5.6772 14.1787   2.687E+00  7.977E-01  5.772E-01
    2  H  5.6394  5.6583  4.7136  -2.981E+00 -1.092E+00 -1.067E+00


                      <<<<< RESTRAINTS >>>>>
  RESTRAINED STRUCTURE ELEMENTS
       TYPE     ATOM ATOM ATOM ATOM       VALUE     FORCE CONSTANT
     RESPOS        1 5.67 5.6714.17     0.00000          100.0
     RESPOS        2 5.67 5.67 4.72     0.00000          100.0


Greetings,
Martin.



On Fri, 19 May 2006 11:55:36 +0200 (CEST)
  Ari P Seitsonen <ari.p.seitsonen at iki.fi> wrote:
> 
> Dear Martin,
> 
>   Did you try giving the constrained position in Bohr instead of Angstrom? 
> With this change your input seemed to work... No guarantee though. ;)
> 
>     Greetings from Paris,
> 
>        apsi
> 
> PS The combination SYMMETRY 0 / TESR 2 sound a bit contradictory to me,
>   maybe it's just because this is a "toy" system?
> 
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>   Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
>   GSM: +33-6-6736 3820
> 
> On Thu, 18 May 2006, Martin Konopka wrote:
> 
>> Dear CPMD developers,
>>
>> I am trying to use the position restraints implemented in CPMD 3.11.1.
>> It seems failing to work. Restraints are not kept. You can see my test
>> example in test_respos_H2.tar.bz2 . (It is rather artificial system
>> - just for the test purpose.)
>>
>> I have also my own implementation of position restraints (which I
>> programmed very recently not knowing that position restraints are
>> to become available in CPMD 3.11.1). My implementation works (but not
>> with geometry optimization). It is only slighly less general in the
>> sense that it uses d0 = 0. If there is an interest I can send patch
>> files for my implementation or even try to correct the existing
>> official implementation in 3.11.1 - please let me know what do you think
>> about it.
>>
>> Greetings,
>> Martin Konopka.
>>
>> ------------------------------------------------------------
>> Dr. Martin Konopka                   tel: +421-(0)2-60291714
>> Dept. of Physics, CCMS               fax: +421-(0)2-65411483
>> Slovak University of Technology
>> Ilkovicova 3, 812 19 Bratislava, Slovakia
>>
>> http://www.ccms.elf.stuba.sk/konopka.html
>> ------------------------------------------------------------
>>

------------------------------------------------------------
Dr. Martin Konopka                   tel: +421-(0)2-60291714
Dept. of Physics, CCMS               fax: +421-(0)2-65411483
Slovak University of Technology
Ilkovicova 3, 812 19 Bratislava, Slovakia

http://www.ccms.elf.stuba.sk/konopka.html
------------------------------------------------------------