Structural evolution of anionic silicon clusters SiN (20 Bai, Jaeil; Cui, Li-Feng; Wang, Jinlan; Yoo, Soohaeng; Li, Xi; Jellinek, Julius; Koehler, Christof; Frauenheim, Thomas; Wang, Lai-Sheng; Zeng, Xiao Cheng. Afiliación Bai J; Department of Chemistry and Center for Materials Research & Analysis, University of Nebraska, Lincoln, Nebraska 68588, USA. J Phys Chem A ; 110(3): 908-12, 2006 Jan 26. Article en En | MEDLINE | ID: mdl-16419988

ABSTRACT

Results of a combined photoelectron spectroscopy and first-principles density-functional study of SiN- clusters in the size range 20 prolate-to-near-spherical shape transition at N = 27 is presented. It is shown that the tricapped-trigonal-prism (TTP) structural motif Si9 found in most low-lying clusters SiN-, 9 adamantane" fragment plus a magic-number cluster (Si6, Si7, Si10) or TTP Si9 in low-lying prolate clusters SiN-, N >or= 20. For 28 lying near-spherical clusters SiN- adopt "stuffed-cage"-like structures where the cages are homologous to carbon fullerenes in the sense that they are composed of only five- and six-membered rings. However the arrangement of the "stuffing" atoms is not yet diamondlike.