Density functional study of beryllium clusters, with gradient correction

By using density functional theory with Becke-Lee-Yang-Parr (BLYP) gradient correction, we have studied the structural and electronic properties of beryllium clusters up to 21 atoms. The theoretical calculations successfully reproduce the experimental bond length and vibrational frequency of the Be 2 dimer and the overestimation of the binding energy is significantly reduced compared to that in previous theoretical work. The Be n clusters with n = 4,10,17 show particularly high stability, consistently with the electron shell model. The size evolution of the electronic properties from van der Waals to covalent and bulk metallic behaviour in Be clusters is discussed.