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Re^2: FIREFLY based comments on speeds and accuracies of SBKJC vs 6-31G?

Siddheshwar Chopra

Dear Alex,
Thats an important information. Thanks again. Alex could you comment on their speeds? Logically if they reduce the no. of basis functions, then they should be really fast. I want to be sure about their speeds before using them. It would be good if you could compare their speeds with the 6-31G and its variants.


On Fri Apr 18 '14 9:10pm, Alex Granovsky wrote
>Dear Siddheshwar,

>for second row elements ECPs are computationally inefficient as
>they remove only single orbital (i.e. 1s) per atom. If you use
>SBK, you still need to add polarization function(s) to get
>reasonable results. SBK basis for Li, Be, B, C, N, O, and F
>atoms has only two L-type (i.e. combined S and P) shells for
>valence electrons and thus it is (approximately) a DZV-quality
>basis set.

>Kind regards,
>Alex Granovsky
>On Tue Apr 15 '14 1:24pm, Siddheshwar Chopra wrote
>>Dear All,
>>This is the first time I am using SBKJC ECPs for the same samples for which I used 6-31G basis sets. Could anyone point out their speed and accuracy comparisons (Firefly based)? As per Jensen's book I read that for the second row elements, SBKJC gives almost same error as that of TZP. And I have never used TZPs. I have till now worked with only 6-31G and variants.


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