Inspired by the possibility to experimentally manipulate and enhance chemical reactivity in
helium nanodroplets, we investigate the effective interaction and the resulting correlations
between two diatomic molecules immersed in a bath of bosons. By analogy with the
bipolaron, we introduce the biangulon quasiparticle describing two rotating molecules that
align with respect to each other due to the effective attractive interaction mediated by the
excitations of the bath. We study this system in different parameter regimes and apply …