>Hi all,
>
>when performing a large QM/MM computation (49 QM atoms, 7 link atoms,
>886 MM atoms) with electrostatic coupling of MM charges to the
>wavefunction (ELSTAT_COUPLING_MODEL=2), ADF crashes with a segmentation
>fault after completing the first MM optimization upon entering the DFT
>module. It happens both on Compaq XP 1000 (Alpha) and Linux systems. The
>program runs happily enough when I use pure MM electrostatics
>(ELSTAT_COUPLING_MODEL=1).
>
>Does anybody know about this problem? Am I doing something wrong?

This is a bug in the QMMM code.

>Related:
>
>When I explicitly select OPTIMIZE METHOD SD in a QM/MM computation, the
>program still appears to perform a BFGS optimization. Has anybody
>encountered this one? Any tips?

Use STEEPEST_DESCENT instead of SD.
This will work.

-- 
Marcel Swart
Theoretische Chemie (MSC) / Moleculaire Dynamica (GBB)
Rijksuniversiteit Groningen
Nijenborgh 4
9747 AG Groningen
The Netherlands
m.swart_at_chem.rug.nl
http://go.to/m.swart