  In electronic structure theory, restricted single-reference coupled cluster
(CC) captures weak correlation but fails catastrophically under strong
correlation. Spin-projected unrestricted Hartree-Fock (SUHF), on the other
hand, misses weak correlation but captures a large portion of strong
correlation. The theoretical description of many important processes, e.g.
molecular dissociation, requires a method capable of accurately capturing both
weak- and strong correlation simultaneously, and would likely benefit from a
combined CC-SUHF approach. Based on what we have recently learned about SUHF
written as particle-hole excitations out of a symmetry-adapted reference
determinant, we here propose a heuristic coupled cluster doubles model to
attenuate the dominant spin collective channel of the quadratic terms in the
coupled cluster equations. Proof of principle results presented here are
encouraging and point to several paths forward for improving the method
further.
