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Re^3: FIREFLY based comments on speeds and accuracies of SBKJC vs 6-31G?

Siddheshwar Chopra

Dear Alex,
In addition to the previous questions, could you also suggest any other better basis sets for 5th row elements which would be a good trade off between speed and accuracy? Say for performing OPT+HESS calculations of MoS2 2D nanosheets.


On Sat Apr 19 '14 6:32pm, Siddheshwar Chopra wrote
>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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