Berlin 2001 – wissenschaftliches Programm
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MO: Molekülphysik
MO 7: Posters Wednesday: Theory: Structure and Dynamics
MO 7.3: Poster
Mittwoch, 4. April 2001, 12:30–15:00, AT3
Differential cross sections for near threshold electron impact dissociation of molecular hydrogen — •Cynthia Sandra Trevisan and Jonathan Tennyson — Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
Electron impact dissociation of molecular hydrogen is considered to be a major route to molecular break-up in cool hydrogen plasmas found in a number of astrophysical environments and in the diverter region of tokamak fusion plasma. It is the rate of electron impact dissociation in the near threshold region which is the important physical quantity. At low energies, the major pathway for the electron impact dissociation of H2 is through excitation to the b 3Σu+ dissociative excited electronic state. We have formulated an expression for the double differential cross sections for electron impact dissociation in terms of T-matrices and performed ab initio calculations using the adiabatic nuclei, energy balance model of Stibbe and Tennyson [1], of total cross sections and angular differential cross sections that can be compared directly with measurements [2]. Energy differential cross sections for the electronic ground state in the ground vibrational v=0 level suggest that the H atoms carry off most of the excess energy. Current calculations on other initial vibrational levels suggest this may not be true for vibrationally excited targets. Progress on this work, as well as extensions to describe deuterium and tritium molecules, will be presented at the conference. References
- [1] D.T. Stibbe and J. Tennyson. New J. Phys., 1 (1998) 2.1
- [2] C.S. Trevisan and J. Tennyson. J. Phys. B: At. Mol. Opt. Phys., submitted