Paper PS-TuP21
Electron Molecule Collisions with Methane

Tuesday, October 29, 2013, 6:00 pm, Room Hall B

Methane is of particular interest due to its use in diamond deposition processes, and presence in fusion and combustion plasmas. Methane is known to be a difficult molecule to simulate, combined with the difficulty of obtaining electronic excitation and dissociation for both theorists and experimentalists alike[1], this presents a relative lack of data for this important molecule.

Quantum-mechanical calculations can be the answer. The calculations presented use the R-Matrix method: where the configuration space is divided into two regions. There is an inner region, where the physics is complicated by exchange and correlation effects, and an outer region, where greatly simplified equations can be solved. The programs used to carry out these calculations are provided by the UKRmol suite. See Tennyson [2][3] for a detailed review of electron-molecule collisions using the R-matrix method. Quantemol-N provides an expert system for running these codes as well as adding extra functionality tailored to provide data for plasma models.

Using Quantemol-N, several different cross sections and properties were calculated for methane, including electron impact elastic, excitation, rotational excitation, differential, momentum transfer, ionisation, and dissociative attachment cross sections. This data can be coverted in the reaction rates and used for modeling of plasma processes.

[1]: M. Ziolkowski et al., J. Chem. Phys., 137, 22A510 (2012)

[2]: J. Tennyson, Phys. Rep. 491, 2-3 (2010)

[3]: J. Tennyson et al, J. Phys. Conf. Series, 86, 012001 (2007)