Density functional calculations of beryllium clusters Be-n, n=2-8

Neutral beryllium clusters Be-n, n = 2-8, were investigated by density func tional techniques. To minimize errors, geometry optimization, frequency and energy calculations were all carried out on the same level of theory, empl oying a large 6-311++G(3df) basis set. The method reproduces well the exper imentally known bond length and vibrational frequency of the dimer, but its binding energy is still significantly overestimated. The computed trends o f the vibrational frequencies, bond lengths and binding energies of the clu sters as a function of the number of atoms are discussed. The binding energ ies are found to increase rapidly as a function of size, and approach the b inding energy of the bulk metal, 54.1 kJ per bond. (C) 2000 Elsevier Scienc e B.V. All rights reserved.