Ground state structures, electronic and optical properties of medium-sized Nan+ (n = 9, 15, 21, 26, 31, 36, 41, 50 and 59) clusters from ab initio genetic algorithm*
1 Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, P.R. China
2 College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024, P.R. China
Received: 29 August 2012
Received in final form: 4 December 2012
Published online: 7 March 2013
Employing genetic algorithm incorporated with density functional theory calculations we determined the lowest-energy structures of cationic Nan+ clusters (n = 9, 15, 21, 26, 31, 36, 41, 50 and 59). We revealed a transition of growth pattern from “polyicosahedral” sequence to the Mackay icosahedral motif at around n = 40. Based on the ground-state structures the size dependent electronic properties of Nan+ clusters including the binding energies, HOMO-LUMO gaps, electron density of states and photoabsorption spectra were discussed. As cluster size increases, the HOMO-LUMO gap of Nan+ cluster gradually reduces and converges to metallic behavior of bulk crystal rapidly. The photoabsorption spectra of Nan+ clusters from our calculations agree with experimental data rather well, confirming the reliability of our theoretical approaches.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2013