[molpro-user] Is it possible to do geometry optimization "by hands" via a do-loop

[Hans-Joachim Werner]

The OPT command does not exist any more. Of course the hessian is  
updated
in each step, and it is also possible to use more accurate hessians  
(either
by computing it during the optimization or using a previously computed  
hessian).
These hessians can be computed at lower level than the energy/gradient  
(see manual).
You can also use the STARTCMD or PROCEDURE options to construct your own
more complicated procedure for the energy calculation (this is more or  
less
like using a do-loop). In case of convergence problems it is sometimes
helpful to use {optg;method,diis}

Am 08.11.2009 um 10:48 schrieb Evgeniy Gromov:

> Dear Developers and Users of Molpro,
>
> I am wondering whether it is possible to do geometry optimization
> via a do-loop, without using "optg". I mean, in some previous  
> version of
> molpro there was the command "opt" which just calculated next geometry
> from (already) available gradients calculated before "opt" with
> "forces". In recent versions there is only the "optg" command which
> crashes if one evaluates gradients inside the optg loop. One could
> of course specify maxit=1 for optg, i.e.
>
> optg,maxit=1
>
> and then organize a loop using "do". In this case
> I however suspect that "optg" might use a new crude model
> Hessian at each optimization step, so that the Hessian
> will be not updated which will result in poor convergence.
> So, I will very appreciate if someone knows how to do what
> geometry optimization "by hands", without automatic "optg".
> Many thanks!
>
> Best regards,
> Evgeniy
>
> -- 
> _______________________________________
> Dr. Evgeniy Gromov
> Theoretische Chemie
> Physikalisch-Chemisches Institut
> Im Neuenheimer Feld 229
> D-69120 Heidelberg
> Germany
>
> Telefon: +49/(0)6221/545263
> Fax: +49/(0)6221/545221
> E-mail: evgeniy at pci.uni-heidelberg.de
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