TURBOMOLE Users Forum

Forum General => Miscellaneous => Topic started by: Marisa on October 08, 2008, 12:35:10 PM

Title: diffuse function for def2- basis set
Post by: Marisa on October 08, 2008, 12:35:10 PM

Hello everyone,

  In Pople's and Dunning's basis set, their are "++" and "aug-" supplement for diffuse function, does def2- basis set in turbomole has similar function?

   Judging from Turbomole set library http://www.ipc.uni-karlsruhe.de/tch/tch1/TBL/tbl.html
seems def2- basis has already included many small exponent Gauss functions; from Phys. Chem. Chem. Phys . , 2 0 0 5 , 7 , 3 2 9 7 – 3 3 , the test set also contains some anions. Does it mean diffuse function is included in def2- basis set already?

  Thank you~

Title: Re: diffuse function for def2- basis set
Post by: Arnim on October 15, 2008, 10:26:15 AM

Hi,

there is no standard extension with diffuse functions for the def2 basis sets.
You can take the flat functions from the aug- basis sets out of the basis set library
and add them manually in the basis file. But you should know what you are doing
in that case.

For most 'standard' applications the diffuse functions don't really improve your
results, but they make the calculation a lot slower, because integral prescreening
will not have an effect anymore. It is probably best to test basis sets on small model systems.

Cheers,
Arnim

Title: Re: diffuse function for def2- basis set
Post by: Marisa on October 16, 2008, 01:57:32 PM

Hello,

  Thanks for your reply. If I employ some diffuse function into def- series, is their any way to construct auxiliary basis set for it?
In addition, seems there are cbas for aug-cc-pVXZ basis, but no jbas. Is that legal to copy cbas to jbas for aug-cc-pVXZ? seems there will miss RI for exchange integral?

Best regards

Title: Re: diffuse function for def2- basis set
Post by: christof.haettig on January 11, 2009, 01:01:18 PM

Using cbas in place of jbas will result in rather large errors in the Hartree-Fock calculation.

Christof