Collisions between two C60 molecules are studied using molecular dynamics simulations. The results show that dumbbell-shaped (C60)2 dimers with almost intact cages can be formed at low collision energies, and when the collision energy is high enough to overcome the fusion barrier, the two colliding C60 molecules fuse to form one large C120 cluster. These coalescence reactions are found to have very clear threshold behavior. The threshold energy of dimerization is dependent on the classical impact parameter between the mass centers of the colliding partners, and on the collisional orientation. The coalescence reactions are shown to be deep inelastic. The total cross section for the coalescence reaction is estimated to be on the order of the area of a circle, that has a radius equal to the diameter of a C60 molecule.

and Pb1-x Snx Te have been measured by use of the 19F(p, αγ) 16O resonance nuclear reaction at 872.1keV with width F=4.2keV. In order to obtain the true range distribution of implanted fluorine from the experimental excitation yield curve, a convolution calculation method is presented, from which the range distribution parameters such as the average projected range Rp, the projected range straggling △Rp and the skewness of the projected range distribution SK were obtained. These experimental range parameters were compared with those obtained by a theoretical calculation and by use of the TRIM89 program, and shows that for all the materials studied here the experimental Re values agree with the theoretical and the TRIM values very well but the experimental range straggling △Re are larger than those obtained by the theoretical calculation and the TRIM89. This phenomenon may be attributed to the enhanced diffusion during the ion implantation.