evolution of binary systems. We consider only field populations here. Rate estimates performed for dense populations in which dynamical interactions between stars are important (i.e., globular clusters and galactic nuclear clusters) have been presented elsewhere [@gultekin; @oleary; @grin2006; @sadowski; @ivan; @downing; @MillerLauburg:2008]. Our Standard model uses the “Nanjing” [@chlambda] $\lambda$ coefficient in the CE energy balance prescription of [@webbink], where the precise value of $\lambda$ depends on the evolutionary stage of the donor, its Zero Age Main Sequence (ZAMS) mass, the mass of its envelope, and its radius. In turn, these quantities depend on metallicity, which in our simulations varies within the broad range $10^{-4}\leq Z \leq 0.03$ (recall that solar metallicity corresponds to $\zsun=0.02$). The values of $\lambda$ for high-mass stars ($M_{ZAMS}>20\msun$) were obtained through private communication with the authors and are not present in [@chlambda].

The impact of the CE outcome on binary populations depends strongly on the evolutionary stage of the donor, as first discussed in [@rarity]. The Standard model does not allow for CE events with HG donors. These stars are not expected to possess a clear core-envelope structure [@ivanovataam], thus making it difficult for them to eject their outer layers during the CE phase. In 