THE MECHANISM OF PHASE-TRANSFORMATION FROM CARBON NANOTUBE TO DIAMOND

The transitional model from carbon nanotube to diamond has been establ ished. The transition has been accomplished from carbon nanotube to ca rbon onion and then to diamond through laser irradiation. The transiti on from tube to onion under laser irradiation experiences the process of structure collapse of the tube and re-organization of carbon cluste rs. Carbon atoms in onions have some sp(3) character due to the insert ion of pentagons in hexagon networks and curling of the structure. So onions are easier than graphite to transform into diamond. Laser irrad iation can give rise to the loss of atoms by sputtering and interstiti al atoms among shells. Because of the surface tension a state of self compression is formed in carbon onions and the pressure can induce the transition from onion to diamond. (C) 1998 Elsevier Science Ltd. All rights reserved.