THE IMPACT OF THE RESOLUTION OF THE IDENTITY APPROXIMATE INTEGRAL METHOD ON MODERN AB-INITIO ALGORITHM DEVELOPMENT

The computation of the two-electron four-center integrals over gaussia n basis functions is a significant component of the overall work of ma ny ab initio methods used today, Improvements in the computational eff iciency of the base algorithms have provided significant impact, Somew hat overlooked are methods that provide approximations to these integr als and their implementation in application software. A partial review of approximate integral techniques focused on the resolution of the i dentity (RI) four-center, two-electron integral approximation is given . The past and current uses of the RI algorithms are presented along w ith possibilities for further exploitation of the technology.