Eur. Phys. J. D 10, 105-114 (2000)
https://doi.org/10.1007/s100530050530

Ab initio molecular dynamics study on Ag_n (n = 4, 5, 6)

¹ Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, P.R. China
² Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
³ Institut für Theoretische Physik, Technische Universität Wien, Vienna, Austria

Received: 5 May 1999
Revised: 20 August 1999
Published online: 15 April 2000

Abstract

Ab initio Molecular Dynamics (MD) method, based on density functional theory (DFT) with planewaves and pse d9126.udopotentials, was used to study the stability and internal motion in silver cluster Ag_n, with . Calculations on the neutral, cationic and anionic silver dimer Ag₂ show that the bond distance and vibrational frequency calculated by DFT are of good quality. Simulations of Ag₄, Ag₅, and Ag₆ in canonical ensemble reveal distinct characteristics and isomerization paths for each cluster. At a temperature of 800 K, an Ag₄ has no definite structure due to internal motion, while for Ag₅ and Ag₆ the clusters maintain the planar structure, with atomic rearrangement observed for Ag₅ but not for Ag₆. At a temperature of 200 K, Ag₄ can exist in two planar structures whilst Ag₅ is found to be stable only in the planar form. In contrast Ag₆ is stable in both planar trigonal and 3D pentagonal structures. Micro-canonical MD simulation was performed for all three clusters to obtain the vibrational density of states (DOS).