Université de Fribourg

Absolute cross sections for dissociative electron attachment to acetylene and diacetylene

May, Olivier ; Fedor, Juraj ; Ibănescu, Bogdan C. ; Allan, Michael

In: Physical Review A, 2008, vol. 77, no. 4, p. 040701

Absolute cross sections for the production of the two astronomy-relevant negative ions H−C≡C⁻ and H−C≡C−C≡C⁻ by dissociative electron attachment to acetylene C₂H₂ and diacetylene C₄H₂ were measured (with a ±25% error bar). Acetylene yielded the C₂H⁻ ion at an electron energy of 2.95 eV with a cross section of 3.6±0.9 pm² and also the C₂⁻ ion at 8.1 eV...

Université de Fribourg

Isotope effect in dissociative electron attachment to acetylene

May, Olivier ; Fedor, Juraj ; Allan, Michael

In: Physical Review A, 2009, vol. 80, no. 1, p. 012706

Absolute partial cross sections for dissociative electron attachment to H–C≡C–H and D–C≡C–D have been measured using a time-of-flight ion spectrometer combined with a trochoidal electron monochromator. For C₂H₂ the present data are in good agreement with the total cross sections measured previously in our laboratory using the total ion-collection method. The present measurements...

Université de Fribourg

Absolute dissociative electron attachment cross sections in acetylene and its deuterated analogue

May, Olivier ; Fedor, Juraj ; Allan, Michael

In: Chimia, 2010, vol. 64, no. 3, p. 173-176

An instrument for the measurement of absolute dissociative electron attachment cross sections was constructed and applied to two prototype molecules, acetylene (C₂H₂) and deuterated acetylene (C₂D₂). The isotope effect at the first dissociative electron attachment band at 3 eV was determined-the cross section for C₂D⁻/C₂D₂ is 14.4 times smaller than that for C₂H⁻/C₂H₂. The...

Université de Fribourg

Absolute cross sections for dissociative electron attachment to HCN and DCN

May, Olivier ; Kubala, D. ; Allan, Michael

In: Physical Review A, 2010, vol. 82, p. 010701

Absolute partial cross sections for the formation of CN⁻ in dissociative electron attachment to HCN and DCN have been measured using a time-of-flight ion spectrometer combined with a trochoidal electron monochromator to be 940pm² for CN⁻/HCN and 340pm² for CN⁻/DCN at peaks of the bands due to the ²Π-shape resonance. The dissociative electron attachment bands were then recorded under...

Université de Fribourg

Dissociative electron attachment to Pt(PF₃)₄—a precursor for Focused Electron Beam Induced Processing (FEBIP)

May, Olivier ; Kubala, Dušan ; Allan, Michael

In: Physical Chemistry Chemical Physics, 2012, no. 9, p. 2979-2982

Experimental absolute cross sections for dissociative electron attachment (DEA) to Pt(PF₃)₄ are presented. Fragment anions resulting from the loss of one, two, three and four PF₃ ligands as well as the Pt(PF₃)F⁻ and the F⁻ ions were observed. The parent anion Pt(PF₃)⁻₄ is too short-lived to be detected. The dominant process is loss of one ligand, with a very large cross section...