Ab initio study of the physical properties of binarySimCn (m+n≤5) nanoclusters

Abstract

An ab initio study of the stability, structural, electronic, vibrational andoptical properties of the most stable silicon–carbon binary nanoclustersSimCn (m+n≤5) has been made. A B3LYP-DFT/6-311G(3df) method has been employed to optimize fullythe geometries of the nanoclusters. The binding energies (BEs), highest occupiedmolecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gaps, bondlengths, ionization potentials (IPs), adiabatic electron affinities (EAs), vibrationalfrequencies, infrared intensities, relative infrared intensities and Raman scatteringactivities have been computed. In the more stable structures, the carbon atomsare in the majority whereas in the less stable structure the reverse is true. Forthe clusters containing all the carbon atoms except one silicon atom, the BEincreases monotonically with the number of carbon atoms. The ground states of theclusters containing even numbers of the carbon atoms are, in general, lower thanthose containing odd numbers of carbon atoms. On the other hand, the lowestunoccupied states of the clusters containing even numbers of carbon atoms liehigher than those containing odd numbers of carbon atoms. All the predictedphysical quantities are in good agreement with the experimental data whereveravailable. The growth of these most stable structures should be possible in theexperiments.