  Density functional theory calculations of the electronic structure of Ce- and
Pu-based heavy fermion superconductors in the so-called 115 family are
performed. The gap equation is used to consider which superconducting order
parameters are most favorable assuming a pairing interaction that is peaked at
(\pi,\pi,q_z) - the wavevector for the antiferromagnetic ordering found in
close proximity. In addition to the commonly accepted $d_{x^2-y^2}$ order
parameter, there is evidence that an extended s-wave order parameter with nodes
is also plausible. We discuss whether these results are consistent with current
observations and possible measurements that could help distinguish between
these scenarios.
