Some criteria concerning the rational vanishing of Whitehead groups

We give several examples of finite groups $G$ for which the rank of the tensor product $\mathbb{Z}{\otimes }_{\mathbb{Z}\mathrm{A}\mathrm{u}\mathrm{t}(G)}$ Wh$(G)$ is or is not zero. This is motivated by an earlier theorem of the first author, which implies as a special case that when this group has nonzero rank, the Whitehead group of any other group (finite or infinite) that contains $G$ as a normal subgroup is rationally nontrivial.