Quick search Find article
Quick search
Find article

High-resolution study of dissociative electron attachment to dipolar molecules at low energies: CH2Br2 and CCl3Br

A Schramm1, M-W Ruf1, M Stano2, S Matejcik2, I I Fabrikant1,3 and H Hotop1

Show affiliations


Using the laser photoelectron attachment method with an energy width ≤ 1 meV at low energies (≤ 172 meV) and an electron beam method (energy width about 70 meV) at higher energies (up to 2 eV), we have determined absolute cross sections σe (E) for dissociative electron attachment to the dipolar molecules CH2Br2 and CCl3Br by normalization to known electron attachment rate coefficients. At thresholds for vibrational excitation of the CH2Br2 molecule, the DA cross section exhibits pronounced structure due to coupling of the attachment process with scattering channels; below the ν3 = 1 onset for the symmetric CBr2 stretch vibration, a clear vibrational Feshbach resonance is observed. At low energies the cross sections σe (E) show an energy dependence between E−1/2 and E−1, in essential agreement with predictions of an extended Vogt–Wannier (EVW) capture model which includes the long-range electron–dipole interaction in addition to the polarization force. The determined absolute values are, however, substantially smaller than those predicted by the EVW model. Semiempirical R-matrix calculations have been carried out which show that at low electron energies (E < 0.15 eV) Br formation from CCl3Br proceeds by s-wave attachment to the anion ground state while a broad peak, observed around 0.6 eV and evolving predominantly into the Cl channel, is due to an excited anion state. Comparisons are made with cross sections and rate coefficients obtained in previous photoelectron attachment work (TPSA) and in electron beam as well as swarm experiments. Based on our joint experimental results for σe (E), we report the electron temperature dependence of the rate coefficients ke (Te) for free electron attachment involving a Maxwellian electron ensemble and a gas at room temperature (TG = 300 K).


PACS

34.80.Lx Recombination, attachment, and positronium formation

31.15.bu Semi-empirical and empirical calculations (differential overlap, Hückel, PPP methods, etc.)

33.60.+q Photoelectron spectra

34.80.Ht Dissociation and dissociative attachment

33.80.Rv Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)

33.20.Tp Vibrational analysis

Subjects

Atomic and molecular physics

Computational physics

Dates

Issue 20 (28 October 2002)

Received 14 June 2002, in final form 30 August 2002

Published 1 October 2002



  1. High-resolution study of dissociative electron attachment to dipolar molecules at low energies: CH2Br2 and CCl3Br

    A Schramm et al 2002 J. Phys. B: At. Mol. Opt. Phys. 35 4179

  2. Electronic instability in bismuth far beyond the quantum limit

    Benoît Fauqué et al 2009 New J. Phys. 11 113012

  3. Galilean covariant Lagrangian models

    E S Santos et al 2004 J. Phys. A: Math. Gen. 37 9771

  4. Local Surface Potential of GaN Nanostructures Probed by Kelvin Force Microscopy

    Gu Xiao-Xiao et al 2003 Chinese Phys. Lett. 20 1822

  5. Vector coherent state representations, induced representations and geometric quantization: II. Vector coherent state representations

    S D Bartlett et al 2002 J. Phys. A: Math. Gen. 35 5625

  6. The mechanism of interaction of dislocations with point defects in ionic crystals

    A V Shuldiner and V A Zakrevskii 2002 J. Phys.: Condens. Matter 14 9555

  7. The IRS 1 Circumstellar Disk, and the Origin of the Jet and CO Outflow in B5

    W. D. Langer et al 1996 ApJ 468 L41

  8. Diffusion-Based Recommendation in Collaborative Tagging Systems

    Shang Ming-Sheng and Zhang Zi-Ke 2009 Chinese Phys. Lett. 26 118903

  9. Mixing of ground states in vertex models

    Jin Hong et al 1998 J. Phys. A: Math. Gen. 31 L515

  10. The decagonal quasicrystal Al65Co15Cu20 studied by the Mössbauer effect

    Zbigniew M Stadnik and Guowei Zhang 2005 J. Phys.: Condens. Matter 17 6599

Related review articles

What's this?
View review articles related to this research to gain an insight into the key trends in this subject area. Related review articles are selected based on PACS/MSC codes, and are no more than three years old.

  1. Strong-field rescattering physics—self-imaging of a molecule by its own electrons
  2. Electron-impact cross sections for deuterated hydrogen and deuterium molecules
  3. Modeling of gas discharge plasma

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.