Author Topic: optimisation from hessian  (Read 5434 times)

monika

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optimisation from hessian
« on: January 22, 2007, 09:45:42 am »
Hello
I would like ask you how can I start optimisation (ri-mp2) from hessian optimized DFT. Which method will be the bast.
 My strukture  has 30 atmos, 440 basis functions, it's open shell. Please for answer.

best regards
« Last Edit: January 22, 2007, 09:53:23 am by monika »

turbomaster

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Re: optimisation from hessian
« Reply #1 on: January 23, 2007, 12:36:54 pm »
Hello

It is possible to use a calculated Hessian matrix for structure optimizations.

1. When using Jobex/Relax combination you have to modify the $forceinit section
of the "control" file to
$forceinit
   carthess
Additionally, if you use internal coordinates you have to activate the conversion
of force constants matrix from Cartesian to internals by specifying
$interconversion on
   cartesian --> internal  hessian
in the "control" file.
The details are also described in the TM manual under
"Calculation of Molecular Structure and Ab Initio Molecular Dynamics"

2. In the Jobex/Statpt combination the calculated Hessian matrix will
automatically be used if any of the sections $hessian, $hessian (projected),
or $nprhessian is present in the "control" file.