  Common experience tells us that a knot significantly weakens the polymer
strand in which it is tied, which in turn leads to more facile chain rupture
under tensile loading. Using first-principles molecular dynamics calculations
we describe the dynamical evolution of the radicals that form after chain
rupture of a single knotted alkane molecule in their very early stages of life.
They are able to recombine, to form cyclic alkanes and to undergo
disproportionation phenomena with nearby chain segments. The breaking of a
single knotted polymer chain under mechanical loading is thus predicted to
reveal phenomena falling in the domain of ultrafast spectroscopy.
