English: This figure shows the energy barriers between different oxygen molecule and (10,0) semiconducting carbon nanotube divacancy configurations. The first energy barrier between physisorbed oxygen and the first chemisorbed oxygen is no more than 50meV and could easily be overcome at room temperature. Whereas the second energy barrier between the first and second chemisorbed oxygen states is roughly 200meV so it is possible to overcome this at room temperature, but it is not very likely. The difference in the size of these energy barriers is because the carbon molecules at the base of the pentagon shape must shift to accommodate a more closely chemisorbed oxygen. This presents a challenge for the manufacturing of carbon nanotubes as this figure demonstrates that divacancy defects are likely to be oxygenated, dramatically changing the electrical properties of the carbon nanotube.