  Linear carbon-based materials such as polyyne and cumulene oligomers provide
a versatile platform for nano-physics and engineering. Direct gap quasi-1D
polyyne structures are promising for the observation of strong and unusual
excitonic eects arising due to the two-dimensional quantum connement. Recently,
we reported on the observation of sharp exciton peaks in low temperature
photoluminescence spectra of polyyne chains. Here, we analyse the time-resolved
optical response of this system. We extend the non-local dielectric response
theory to predict the exciton radiative lifetime dependence on the band-gap
value and on the length of the chain. A good agreement between the experiment
and the theory is achieved.
