Rapid evaluation of molecular integrals with ETOs

In this article, we discuss a way in which the theory of hyperspherical harmonics may be used for rapid evaluation of difficult molecular integrals when exponential‐type orbitals (ETOs) are used as a basis. One of us (J.E.A.) has implemented the method, and programs are available for general use. As a byproduct of this work, we are also able to evaluate generalized scattering factors for ETOs which allow first‐order density matrices to be measured experimentally using high‐quality X‐ray diffraction data. © 2015 Wiley Periodicals, Inc.