Vol.6, No 1, 2008 pp. 89 - 98
DOI 10.2298/FUPCT0801089M
UDC  539.12-17

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LOW-ENERGY ELECTRON DRIVEN PROCESSES IN ICES: SYNTHESIS REACTIONS AND SURFACE FUNCTIONALIZATION
I. Martin, L. Amiaud, R.Azria, A. Lafosse
Université Paris-Sud, CNRS, Laboratoire des Collisions Atomiques et Moléculaires, UMR 8625 Bât. 351, UPS-11, Orsay, F-91405

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Abstract. Low-energy electrons, and subexcitation energy electrons in particular, have the ability to induce efficiently chemical modifications within condensed molecular films and at substrate surfaces. By taking advantage of the Dissociative Electron Attachment (DEA) process, which leads to selective bond cleavages, the induced reactivity can be controlled solely by the electron energy. Two illustrative examples of induced reactivity and substrate functionalization achieved by low-energy electron processing of condensed molecules studied by means of High Resolution Electron Energy Loss Spectroscopy (HREELS) are reviewed, and special interest is given to the possibility of proposing overall reaction mechanisms. The resonant decarboxylation reaction in condensed films of trifluoroacetic acid CF₃COOH induced by electrons at ~1 eV involves the formation of the transient species [CF₃COOH]^#- and the further formation of CO₂ by a concerted mechanism. Diamond substrate functionalization by CH₂CN organic groups through C_diam—C and C_diam—N bonds is performed by 2 eV electron irradiation of condensed acetonitrile CH₃CN and involves reactants formed by DEA, that are neutral radicals H^• and molecular anions [H₂CCN]^-.
Key words:  Dissociative Electron Attachment, Electron Induced Reactivity, Selectivity, Functionalization, Diamond, High Resolution Electron Energy Loss Spectroscopy

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PROCESI U LEDU INDUKOVANI ELEKTRONIMA NISKE ENERGIJE: 
REAKCIJE SINTEZE I FUNKCIONALIZACIJA POVRŠINE Elektroni niskih energija ispod praga za jonizaciju mogu efikasno prouzrokovati hemijske promene na površini i unutar kondenzovanih molekularnih filmova. Koristeći proces disocijativnog zahvata elektrona, koji uzrokuje selektivno kidanje molekulskih veza, indukovana reaktivnost može biti kontrolisana samo podešavanjem energije elektrona. Dva ilustrativna primera ovakve indukovane reaktivnosti i funkcionalizacije površine, postignute procesiranjem kondenzovanog molekularnog filma elektronima niske energije i studirana pomoću spektroskopije gubitka energije elektrona visoke rezolucije(HREELS), su prikazana u ovom radu, pri čemu je poseban interest usmeren ka mogućnošću da se predloži opšti mehanizam rekacija. Rezonantna reakcija dekarboksilacije u kondenzovanom filmu trifluor-sirćetne kiseline CF₃COOH prouzrokovana elektronima energije ~1 eV uključuje formiranje prelaznih sistema [CF₃COOH]^#- i dalje formiranje CO2 usklađenim mehanizmom. Funkcionalizacija dijamantskog supstrata pomoću CH₂CN organskih grupa preko C_diam—C i C_diam—N veza je postugnuta bombardovanjem kondenzovanog acetonitrila CH3CN elektronima energije 2 eV, i uključuje reaktante formirane disocijativnim elektronskim zahvatom, neutralne radikale H^• i molekularne negativne jone [H2CCN]^-.