Theoretical Investigation Of GeSiC Ternary Semiconductor Microcluster

In the past few decades, considerable interest has been paid to the structures and properties of pure carbon, silicon and germanium clusters due to both fundamental and technological reasons. This paper presents a systematical study of the ground state structures, vibrational frequencies, HOMO-LUMO energy gap and other electronic properties of ternary semiconductor C-rich clusters using the Density Functional theory (molecular orbital MO) method, we also firstly predict systematically the aromaticity in A3R3+,AB2R3+,GeSiCR3+ and A4R42+ (A,B= Ge, Si,C,R=H,CH3,SiH3) semiconductor-core-containing systems employing accurate ab initio method: Moller-Plesset second-order (MP2) perturbation .theory.Firstly , investigations on binary semicondutor mircoclusters AB(A,B= Ge,Si,C) are performed using various methods (DFT and CISD) and a relative bond strength-order C-C>C-Si>C-Ge>Si-Si>Si-Ge>Ge-Ge is found. Then we performed studies on low-lying energy structures and their properties of ternary C-rich clusters Ge1SimCn(1+m+n<10) in detail and the results suggest that their stable ground states adopt linear or near-linear chain, or cyclic planar geometries, much different from the three-dimensional ground state structures of pure Sin or Gen clusters.The most strictly and thoroughly quantitative and qualitative analysis is made on the aromaticites in A3R3+,AB2R3+,GeSiCR3+and A4R42+ (A,B=Ge, Si,C,R= H, CH3, SiH3) semiconductor-core-containing systems at MP2 level. The highest occupied molecular orbitals (HOMOs) of corresponding systems are found to be fully delocalized IT molecular orbitals and all the clusters systems have relatively large Nuclear-Independent-Chemical-Shifts (NICS) at the three-or four-membered ring centers, indicating these systems exhibit aromatic properties. We make the conclusion that all these systems have aromatic properties based on their energetic, geometrical and nucleus magnetic properties(NICS values).