Faculty of Science and Engineering, Curtin University
Electron collisions with molecules: Convergent-Close coupling method (CCC)
We have developed a computer code to perform large-scale close-coupling calculations for electron collisions with molecules. The CCC code has been extensively applied to molecular hydrogen (H2) and its ion (H2+) and their isotopologues. We can take into account all major reaction channels. Calculations are performed in the fixed-nuclei approximation and then extended to adiabatic nuclei approach that allows us to estimate effects of nuclear motion and produce a comprehensive set of vibrationally resolved cross sections including dissociation cross sections.
We are in process of testing of the computer code for vibrational close coupling that will allows us to determine accurate cross sections for low-energy vibrational excitations.
We are planning to extend the method to other diatomic molecules, such as Li2, LiH, HeH+, etc. that are important for fusion.
Electron collisions with atoms: Convergent-Close coupling method (CCC)
The CCC method has been extensively applied to large number of atoms. For light atoms we have used the nonrelativistic formulation while for heavy atoms we have developed a fully relativistic approach.
Recently we have been involved in producing the recommended set of cross sections for Be atom and its ions. We have investigated electron collisions with lithium (Li), gallium (Ga) and lead (Pb) atoms and are planning to undertake comprehensive studies of electron collisions with tin (Sn) atoms. All these atoms are relevant for fusion research.
Photon collisions with atoms and molecules
This is a new project initiated only this year. We have developed an efficient method for calculation of photon-atom Rayleigh and Raman scattering cross sections and applied it to hydrogen atom. The method is based on the complex exterior scaling approach and allows for a straightforward generalization to more complex atoms and molecules.
Heavy particle collisions (ion-atom and ion-molecule)
We have developed a semi-classical CCC method to solving collisions problems with heavy particles. The method have been applied to proton-hydrogen and proton-lithium collisions and will be extended in future to collisions with tin and gallium atoms as well as to highly charged ion projectiles.
[1] M. C. Zammit et al., "Complete Solution of Electronic Excitation and Ionization in Electron-Hydrogen Molecule Scattering", Physical Review Letters116, 233201 (2016). [link to article]
[2] M. C. Zammit et al., "Electron– and positron–molecule scattering: development of the molecular convergent close-coupling method", Journal of Physics B: Atomic, Molecular and Optical Physics50, 123001 (2017). [link to article]
[3] M. C. Zammit et al., "Electron-impact excitation of molecular hydrogen", Physical Review A95 (2017). [link to article]
[4] D. V. Fursa et al., "Electron mass stopping power in H2", Physical Review A96, 022709 (2017). [link to article]
[5] J. K. Tapley et al., "Vibrationally resolved electron-impact excitation cross sections for singlet states of molecular hydrogen", Journal of Physics B: Atomic, Molecular and Optical Physics51, 144007 (2018). [link to article]
[6] M. Zawadzki et al., "Time-of-flight electron scattering from molecular hydrogen: Benchmark cross sections for excitation of the X1Σg+→b3Σu+ transition", Physical Review A97, 050702 (2018). [link to article]
[7] L. H. Scarlett et al., "Electron-impact dissociation of molecular hydrogen into neutral fragments", The European Physical Journal D72, 34 (2018). [link to article]
[8] D. V. Fursa and I. Bray, "Fully Relativistic Convergent Close-Coupling Method for Excitation and Ionization Processes in Electron Collisions with Atoms and Ions", Physical Review Letters100, 113201 (2008). [link to article]
[9] I. Bray, "Calculation of electron-impact ionization of lithium-like targets", Journal of Physics B: Atomic, Molecular and Optical Physics28, L247-L254 (1995). [link to article]
[10] D. V. Fursa and I. Bray, "Electron scattering from atomic gallium", Journal of Physics: Conference Series185, 012008 (2009). [link to article]
[11] K. Mcnamara, D. V. Fursa and I. Bray, "Efficient calculation of Rayleigh and Raman scattering", Physical Review A98, 043435 (2018). [link to article]
[12] I. B. Abdurakhmanov et al., "Proton scattering from excited states of atomic hydrogen", Plasma Physics and Controlled Fusion60, 095009 (2018). [link to article]
[13] I. B. Abdurakhmanov, A. S. Kadyrov and I. Bray, "Wave-packet continuum-discretization approach to ion-atom collisions: Nonrearrangement scattering", Physical Review A94, 022703 (2016). [link to article]
[14] I. B. Abdurakhmanov et al., "Wave-packet continuum-discretization approach to ion-atom collisions including rearrangement: Application to differential ionization in proton-hydrogen scattering", Physical Review A97, 032707 (2018). [link to article]