Absolute dissociative electron attachment cross sections in acetylene and its deuterated analogue.
نویسندگان
چکیده
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 results play a central role in validating recent theoretical work of Chourou and Orel. The dominant fragments at the second dissociative attachment band around 8 eV are the light fragments H- or D-. These bands exhibit weaker isotope effects.
منابع مشابه
Dissociative electron attachment cross sections for H2 and D2.
New measurements of the absolute cross sections for dissociative electron attachment (DEA) in molecular hydrogen and deuterium are presented which resolve previous ambiguities and provide a test bed for theory. The experimental methodology is based upon a momentum imaging time-of-flight spectrometer that allowed us to eliminate any contributions due to electronically excited metastable neutrals...
متن کاملElectron scattering in HCl: An improved nonlocal resonance model
We present an improved nonlocal resonance model for electron-HCl collisions. The short-range part of the model is fitted to ab initio electron-scattering eigenphase sums calculated using the Schwinger multichannel method, while the long-range part is based on the ab initio potential-energy curve of the bound anion HCl−. This model significantly improves the agreement of nonlocal resonance calcu...
متن کاملLow-energy electron collisions with CH3Br: the dependence of elastic scattering, vibrational excitation, and dissociative attachment on the initial vibrational energy
Using the laser photoelectron attachment (LPA) method at an energy width of 1–2 meV, the Br− yield due to dissociative electron attachment to the molecule CH3Br has been measured over the energy range 1–180 meV at a gas temperature of 600 K. The data clearly exhibit the vibrational Feshbach resonance predicted by Wilde et al. (2000 J. Phys. B: At. Mol. Opt. Phys. 33 5479) and associated with th...
متن کاملRovibrationally enhanced dissociative electron attachment to molecular lithium.
Wadehra JM. Rovibrationally enhanced dissociative electron attachment to molecular lithium. We have investigated the role played by initial rovibrational excitation of Liz on the cross sections and rates for dissociative electron attachment to the molecule. For a given internal energy, the vi-brational excitation enhances the attachment cross section more than the rotational excitation, The att...
متن کاملImportance of nonresonant scattering in low-energy dissociative electron attachment to molecular hydrogen.
A central premise of nearly all theories of dissociative electron attachment is that this process is resonance driven. Neglect of nonresonant scattering, although appropriate for electron-molecule systems with narrow (long-lived) resonances, is problematic for the e-H2 system, which has one of the broadest known resonances. Using the nonadiabatic phase-matrix method we have found that at energi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Chimia
دوره 64 3 شماره
صفحات -
تاریخ انتشار 2010