CCL:G: ORCA questions

[Daniel Jana <dfjana++gmail.com>]

 Sent to CCL by: Daniel Jana [dfjana(!)gmail.com]
 Hello,
 Ramon Crehuet rcsqtc(a)iiqab.csic.es wrote:
>  Sent to CCL by: Ramon Crehuet [rcsqtc*|*iiqab.csic.es]
>  Dear CCLers,
>  I have a couple of questions regarding the use of ORCA.
>  1) Is it possible to freeze (=fix) the position of certain atoms during
>  an optimization?
>  
Yes it is. You need to insert a group called "%geom
 Constraints". Check
 the manual in pages 86 and 87.
>  2) Is there any control on the memory available to the program? Other
>  packages such as gaussian or gamess need the user to give the available
>  memory for each run. This in some cases determines the algorithm to use.
>  Is there any way to do that with ORCA?
>  
I never used any option for this however MaxCore seems to be what you
 need. You can use it more or less like this:
 %mp2 MaxCore 1000 end
the value comes in MB. There is an email in the orca mailing list from
 October last year in which Frank Neese mentions that the program isn't
 very strict in following the values so you should give it some extra
 space. Not sure if in newer versions things have changed.
 Best,
 Daniel