Prescreening and efficency in ECP integrals

This work details new, efficient schemes for the prescreeing and evaluation of integrals over effective core potenitals (ECPs). The prescreeing is combined with a systematic rescaling procedure to give a close bound within approximately 0.1% of the true value. 

A numerically stable recursive integration routine shows speedups of roughly 40 times when compared with quadrature-based methods.

An open-source ECP integrals library (libecpint) based on this work is available on GitHub and is described in a Journal of Open Source Software article.

Prescreening and efficiency in the evaluation of integrals over ab initio effective core potentials. R. A. Shaw and J. G. Hill, J. Chem. Phys., 2017, 147, 074108.

libecpint: A C++ library for the efficient evaluation of integrals over effective core potentials. R. A. Shaw and J. G. Hill, Journal of Open Source Software, 2021, 6, 3039.