Evidence of CF2 Loss from Fluorine-Rich Cluster Anions Generated from Laser Ablation of Graphite Fluoride.

Abstract

A mass spectrometric analysis of the anionic and cationic species generated by laser ablation of graphite fluoride (GF) and graphite targets performed under identical sets of conditions is presented. Under conditions that produce typical C n- cluster mass distributions from ablation of graphite, the mass spectra of anionic species generated by ablation of GF are congested with overlapping stoichiometric patterns such as C nF2 n and C nF(2 n-2). Some of the molecular formulas for these clusters, such as C6F6, C6F12, and C7F8, are evocative of stable neutral fluorocarbons. Additionally, the GF-ablation generated mass peaks broaden at higher masses more than the graphite-based counterparts, which may indicate cluster fragmentation. Furthermore, a pattern of fragmentation via loss of CF2 is observed and is reminiscent of previous studies which determined CF2 loss during thermal decomposition. No species were seen in the mass spectra of the cationic species generated from laser ablation of GF, while, under the same conditions, typical C n+ cluster distributions were observed.