1ST-PRINCIPLES MOLECULAR-DYNAMICS STUDY OF CARBON CLUSTERS

A generalized tight-binding molecular-dynamics technique that correctl y treats interactions in nontetrahedral as well as multicoordinated co valent systems is used to obtain equilibrium geometries for carbon clu sters of arbitrary size. For N less-than-or-equal-to 10 the ground sta tes are determined to be linear chains for odd N and closed rings for even N. The minimum-energy cyclic structures exhibit symmetry-lowering in-plane distortions rather than being regular polygons. These findin gs are in complete agreement with available ab initio results. Large c lusters of atoms are used to demonstrate the validity of the method to simulate bulklike diamond and single-layer graphitic structures. The well-known 2 x 1 reconstruction for the (001) face is observed for the diamond cluster.