SiC bonding in (C60)nSim clusters

P. Mélinon; F. Tournus; B. Masenelli; A. Perez; M. Pellarin; J. Lermé; M. Broyer; B. Champagnon

doi:10.1007/s100530170124

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Atomic, Molecular, Optical and Plasma Physics

Eur. Phys. J. D 16, 337-340 (2001)
https://doi.org/10.1007/s100530170124

SiC bonding in (C₆₀)_nSi_m clusters

P. Mélinon¹^a, F. Tournus¹, B. Masenelli¹, A. Perez¹, M. Pellarin², J. Lermé², M. Broyer² and B. Champagnon³

¹ Département de Physique des Matériaux, Université Claude Bernard-Lyon 1, 69622 Villeurbanne, France
² Laboratoire de Spectrométrie Ionique et Moléculaire, Université Claude Bernard-Lyon 1, 69622 Villeurbanne, France
³ Laboratoire de Physico-Chimie des Matériaux Luminescents, Université Claude Bernard-Lyon 1, 69622 Villeurbanne, France

Corresponding author: ^a pmelinon@dpm.univ-lyon1.fr

Received: 15 November 2000
Published online: 15 September 2001

Abstract

This paper deals with a new type of SiC bonding where silicon atom seems to bridge C₆₀ molecules. We have studied films obtained by deposition of (C₆₀)_nSi_m clusters prepared in a laser vaporization source. Prior deposition, free ionized clusters were studied in a time-of-flight mass spectrometer. Mixed clusters (C₆₀)_nSi_m were clearly observed. Abundance and photofragmentation mass spectroscopies revealed the relatively high stability of the (C₆₀)_nSi $_n^+$ , (C₆₀)_nSi $_{n-1}^+$ and (C₆₀)_nSi $_{n-2}^+$ species. This observation is in favor of the arrangement of these complexes as polymers where the C₆₀ cages may be bridged by a silicon atom. Free neutral clusters are then deposited onto substrate making up a nanogranular thin film ( $\simeq$ 100 nm). The film is probed by Auger and X-ray photoemission spectroscopies, but above all by surface enhanced Raman scattering. The results suggest an unusual chemical bonding between silicon and carbon and the environment of the silicon atom is expected to be totally different from the sp³ lattice: ten or twelve carbon neighbors might surround silicon atom. The bonding is discussed to the light of the so-called fullerene polymerization as observed for pure fullerite upon laser irradiation. This opens a new route for bridging C₆₀ molecules together with an appreciable energy bonding, since the usual van der Waals bonding in fullerite could be replaced by an ionocovalent bond. Such an assumption must be checked in the future by XAS and EXAFS experiments.