[CPMD-list] PRFO question

[Erik Santiso]

Hi all,

I have (another) question about starting a PRFO calculation using a
Hessian from a previous geometry optimization. In this case I have some
atoms in the system that are fixed (with FIX ATOMS). If I run a
vibrational analysis for such a system, CPMD (version 3.9.1) does not
generate a HESSIAN file. In order to create one, I re-run the vibrational
analysis with the constraints removed and RESTART VIBANALYSIS. The problem
is, if I then use this Hessian to start a P-RFO calculation (with RESTART
HESSIAN and PRFO HESSTYPE 1, and putting the constraints back in), CPMD
complains:

HESSIN | NUMBER OF PARAMETERS NOT CONSISTENT  234  42 (I have 14 movable
atoms and 64 fixed ones)
HESSIN | BAD HESSIAN FILE    ./HESSIAN

and goes on trying to generate an empirical Hessian etc.

I've tried using RESTART PHESS and HESSIAN PARTIAL, but CPMD complains
that there is no partial Hessian information on the restart file. So the
question is: is there a way to either (1) Get CPMD to generate a Hessian
file with the correct info from a vibrational analysis when some of the
atoms are fixed (I thought of just changing the number of parameters in
the header of the HESSIAN file, but a little voice in my head says this
may not be a good idea) or (2) Get CPMD to copy the right part of the
Hessian onto the PRFO partial Hessian? The truth is that I could just let
CPMD calculate the Hessian again (with PRFO HESSTYPE 0), but it seems a
waste of computing time...

Sorry for the long question, and many thanks for any suggestions!

Erik.

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