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evaleev / libint

Libint: high-performance library for computing Gaussian integrals in quantum mechanics
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erf-attenuated nuclear integrals #323

Closed philippwo closed 5 months ago

philippwo commented 5 months ago

Dear All, when using libint2 to calculate erf-attenuated nuclear-attraction integrals, the operator is defined as: - \sum Z_I erf(|r-R_I|)/|r-R_I| which takes into account the position (R_I) and the charge (Z_I) of the nucleus. If I wanted to transfer these integrals to non-nuclear charges (e. g. in PCM solvation models), the 'width' (Zeta_I) of the nucleus would also enter the operator as in: - \sum Z_I erf(Zeta_I *|r-R_I|)/|r-R_I| (example for this operator can be found in eq. 6 in 10.1021/acs.jctc.5b00370)

As far as I can see, that factor has a non-trivial effect, since it is within the error-function. Is this operator available in libint? Best regards, Philipp

JonathonMisiewicz commented 5 months ago

Yes. See example usage in the sample code here, where omega is set as the first parameter in the params tuple. You must use Libint 2.8.0 or newer for this, as #279 fixed a bug in these particular integrals.

philippwo commented 5 months ago

Thanks a lot for your help and the fast reply!