[CPMD-list] USPP: H_{2}O

[Dr. Balasubramanian Sundaram]

Dear All,
   We are able to optimize geometry for water monomer as well as 
water dimer system, using:

a) LDA based functionals that came with Vanderbilt's USPP code
b) BLYP based functionals that came with the CPMD PP Library.

We wanted to gain experience in using USPP with BLYP. We generated 
(we beleive so!) the USPP's for oxygen and hydrogen using BLYP 
exchange/correlations, and used these PPs with CPMD to optimize 
the geometry of one water molecule.

The initial configuration of the molecule is very close to the expected
final configuration.

We have tried several combinations of optimization schemes, but we are
unable to converge the wavefunction to anything better than 7.0E-4
(GEMAX).
We tried even CONVERGENCE RELAX {5} option. 

I noticed that Dr. Christian Tuma too had mentioned this in a mail of 
30 Oct. 2002 (Item # 7).

I have attached the input file below. I would appreciate if you could
point
out any mistakes that we are committing.

The other possibility could be that there is something wrong in the way
we
are constructing the USPP with BLYP.

Many thanks!

Best,
Bala
-----------------------------------
&CPMD
 OPTIMIZE GEOMETRY COMBINED
 MAXSTEP
 5000
 STORE
 20
 TIMESTEP
 5.0
 CONVERGENCE GEOMETRY 
 1.0D-4
 CONVERGENCE RELAX
   5
 ISOLATED MOLECULE
 INITIALIZE WAVEFUNCTION RANDOM
 STRUCTURE BONDS ANGLES
&END

&SYSTEM
 ANGSTROM
 CELL 
 10.0 1.0 1.0 0.0 0.0 0.0
 SYMMETRY
 1
 CUTOFF
 25.0
&END

&DFT
  FUNCTIONAL BLYP 
&END 

&ATOMS
*001-H-gbl--sb.uspp BINARY
  LMAX=S
      2
   -0.7731 0.0000 0.0000 1 0
    0.7731 0.0000 0.0000 1 0

*008-O-gbl--sb.uspp BINARY
  LMAX=P
   1
   0.0000 0.5953 0.0000  8 0

&END
------------------------------------------------------------------------