Density functional calculations of beryllium clusters Ben, n=2–8 Original Research Article

Neutral beryllium clusters Ben, n=2–8, were investigated by density functional techniques. To minimize errors, geometry optimization, frequency and energy calculations were all carried out on the same level of theory, employing a large 6-311++G(3df) basis set. The method reproduces well the experimentally known bond length and vibrational frequency of the dimer, but its binding energy is still significantly overestimated. The computed trends of the vibrational frequencies, bond lengths and binding energies of the clusters as a function of the number of atoms are discussed. The binding energies are found to increase rapidly as a function of size, and approach the binding energy of the bulk metal, 54.1 kJ per bond.