  Chaotic three-body interactions may lead to the formation of
gravitational-wave sources. Here, by modelling the encounter as a series of
close, non-hierarchical, triple approaches, interspersed with hierarchical
phases, in which the system consists of an inner binary and a star that orbits
it, we compute the pericentre probability distribution, and thereby the
in-spiral probability in any given binary-single encounter. We then consider
the indirect influence of binary-single encounters on the population of
gravitational-wave sources, by changing the eccentricity distribution of hard
binaries in clusters; we calculate this distribution analytically, by requiring
that it be invariant under interactions with single stars.
