The optimized geometries, stability, and magnetic properties of cationic clusters Si7 + , Si6Mn+ , and Si5Mn2 + have been determined by the method of density functional theory using the B3P86/6-311+G(d) functional/basis set. Their electronic configurations have been analyzed to understand the influence of substituting Si atoms by Mn atoms on the structural and magnetic aspects of Si7 + . | Vietnam Journal of Science and Technology 56 (1) (2018) 64-70 DOI: STABILITY AND ELECTRONIC PROPERTIES OF ISOMORPHOUS SUBSTITUTED Si7-xMnx+ Nguyen Thi Mai1, Nguyen Thanh Tung1,*, Ngo Tuan Cuong2, # 1 Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi 2 Center for Computational Science and Department of Chemistry, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Ha Noi * Email: tungnt@, #Email: cuongnt@ Received: 11 July 2017; Accepted for publication: 26 October 2017 Abstract. The optimized geometries, stability, and magnetic properties of cationic clusters Si7+, Si6Mn+, and Si5Mn2+ have been determined by the method of density functional theory using the B3P86/6-311+G(d) functional/basis set. Their electronic configurations have been analyzed to understand the influence of substituting Si atoms by Mn atoms on the structural and magnetic aspects of Si7+. It is shown that the manganese dopant does not alter the structure of the silicon host but significantly changes its stability and magnetism. In particular, while the magnetic moment of Si7+ is 1 µB, Si5Mn2+ exhibits a strong magnetic moment of 9 µB and that of Si6Mn+ takes a relatively high value of 4 µB. Among studied clusters, the pentagonal bipyramid Si5Mn2+ is assigned as the most stable one. Keywords: cluster silicon, density functional theory. Classification numbers: ; . 1. INTRODUCTION Investigations of the geometries, electronic structures, energetics, and reactivity of atomic clusters have attracted significant interest in recent years. Among the atoms clusters that have been studied, the silicon clusters are of particular interest to scientists [1 - 2]. Silicon has been and continues to be one of the most widely used elements in various semiconductor applications such as solar cells and microelectronics. For some small Sin clusters, the ground-state geometries have been studied by using many .
