  Chemisorption is one of the active research areas in carbon materials. The
occurrence of the monoatomic carbon chain can be made by surrounding the double
walled carbon nanotube and meanwhile worldwide efforts have been made to create
the extraction technique for unlashing the carbon chains from the enclosure.
Here we report an extensive study of the kink structure in the free standing
carbon nanowires. Our Monte Carlo simulation considers the multi-monoatomic
carbon chains laterally interacted by the Van der Waal force. Despite the
linearity of the carbon nanowires is independent of chain length at low
temperatures, the same situation does not hold at high temperatures. Disordered
kink structure is observed in the short carbon chains especially above Peierls
transition temperature. For instance, the average kink angle of 50-atoms carbon
nanowire is as large as 35 degree at 800K. We have provided an important
inspection that any physical property of the finite-length carbon chain
predicted by ab-initio calculation should reconsider the atomic rearrangement
due to the thermal instability. Apart from this, the kink structure in the
nanowires likely increases the probability of attaching negatively charged
atoms which is an encouragement to find the next generation materials for
chemisorption.
