We describe the implementation of the spin-unrestricted Laplace transform fourth-order perturbative triples correction. A reduction in the computational scaling with respect to canonical implementations is attained without relying on the large molecule asymptote. The intrinsic scaling difficulties that the Laplace equations exhibit upon increasing the size of the basis sets are properly addressed. The method is suited for medium-size molecules.
Dedicated to Professors Petr Čársky, Ivan Hubač, and Miroslav Urban on the ocasion of their 60th birthdays.