[CPMD-list] too long Si-O bond-length from geometry optimization

[bala at jncasr.ac.in]

dear Liu,
   Is there a typographical error in the line containing the Al
pseudopotential? (KLEINMAN-YLANDER instead of KLEINMAN-BYLANDER)?

Bala

> Dear CPMDers,
>
> I used CPMD to optimize a mineral containing Si, Al, O and H within a
> fixed
> cell. The bond lenths of Al-O, O-H are very close to the experimental
> values, whereas the Si-O lengths are about 1.72 angstrom, much longer than
> the experimental value (about 1.61 angstrom). Could you give some
> suggestions ?
> The following is part of the input file.
> &CPMD
>
>
>
>   OPTIMIZE GEOMETRY
> XYZ
>   HESSIAN
> UNIT
>
>
>
>   CONVERGENCE
> ADAPT
>
>   0.02
>
>   CONVERGENCE
> INITIAL
>
>   1.0D-4
>
>   CONVERGENCE
> ORBITALS
>   5.0D-5
>
>   CONVERGENCE
> GEOMETRY
>   4.0D-4
>
>
>
>     ODIIS
> NO_RESET=40
>
>
> 5
>
>
>
>     LBFGS
> NREM
>
>
> 20
>
>
> &END
>
>
>
> &DFT
>
>   FUNCTIONAL
> BLYP
>
>
>
>
>
> &END
>
>
>
> &SYSTEM
>
>
>
>
> SYMMETRY
>
>
> 14
>
>
> ANGSTROM
>
>   CELL ABSOLUTE
> DEGREE
>
>    5.1535 8.9419 7.3906 91.9260 105.0460 89.7970
>
>
> CUTOFF
>
>    70.0
>
> &END
>
>
>
> &ATOMS
>
> *O_MT_BLYP.psp
> KLEINMAN-BYLANDER
>
>  LMAX=P
>
>  18
> ...
>
>
> *H_MT_BLYP.psp
> KLEINMAN-BYLANDER
>
>  LMAX=S
>
>  8
> ...
>
>
> *Si_MT_BLYP.psp
> KLEINMAN-BYLANDER
>
>  LMAX=P
>
>  4
> ...
>
>
> *Al_MT_GIA_BLYP.psp
> KLEINMAN-YLANDER
>  LMAX=D
> LOC=0
>
>  4
> ...
>
>
> &END
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