The study of the gas-phase reactions of the Si+ ions with nitrogen trifluoride (NF3) was performed by quadrupole ion trap mass spectrometry and ab initio calculations. Experimental results display a thermodynamically favoured reaction cascade starting from the reactants corresponding to multiple fluorine abstraction, which ultimately yields neutral fluorosilane by fluoride abstraction. A parallel, slightly endothermic channel is observed starting from the reactants and generating the NF2+ and SiF products. The study of the potential energy hypersurface of the Si+(2P) + NF3 system evidenced the initial formation of the N-coordinated Si+–NF3 adduct. Subsequent rearrangements and atom migrations lead to the FSi+–NF2 isomer, whose dissociation yields SiF+ and NF2 as products. Theoretical energy profiles show that this pathway is strongly exothermic (about −100 kcal mol−1) and that the dissociation of the FSi+–NF2 species to the endothermic (+6 kcal mol−1) channel products (NF2+ and SiF) is extremely unlikely for ground-state reactants.

Gas-phase ion chemistry of Si+ and NF3: an experimental and theoretical study

ANTONIOTTI, Paola;OPERTI, Lorenza;RABEZZANA, Roberto;TURCO, Francesca;
2006-01-01

Abstract

The study of the gas-phase reactions of the Si+ ions with nitrogen trifluoride (NF3) was performed by quadrupole ion trap mass spectrometry and ab initio calculations. Experimental results display a thermodynamically favoured reaction cascade starting from the reactants corresponding to multiple fluorine abstraction, which ultimately yields neutral fluorosilane by fluoride abstraction. A parallel, slightly endothermic channel is observed starting from the reactants and generating the NF2+ and SiF products. The study of the potential energy hypersurface of the Si+(2P) + NF3 system evidenced the initial formation of the N-coordinated Si+–NF3 adduct. Subsequent rearrangements and atom migrations lead to the FSi+–NF2 isomer, whose dissociation yields SiF+ and NF2 as products. Theoretical energy profiles show that this pathway is strongly exothermic (about −100 kcal mol−1) and that the dissociation of the FSi+–NF2 species to the endothermic (+6 kcal mol−1) channel products (NF2+ and SiF) is extremely unlikely for ground-state reactants.
2006
255-256
225
231
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VND-4J8KNRP-1&_user=525216&_coverDate=09%2F01%2F2006&_rdoc=31&_fmt=high&_orig=browse&_srch=doc-info(%23toc%236176%232006%23997449999%23630420%23FLA%23display%23Volumes)&_cdi=6176&_sort=d&_docanchor=&_ct=41&_acct=C000026382&_version=1&_urlVersion=0&_userid=525216&md5=4c2ad46d74182742cacae1b1cb45f308
Gas-phase ion chemistry; Ab initio calculations; Ion trap mass spectrometry; Silicon ions; Nitrogen trifluoride
P. ANTONIOTTI; L. OPERTI; R. RABEZZANA; F. TURCO; GA VAGLIO
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/23184
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