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Calculations are performed for electron collision with the methylene molecular ion C H 2 + in its bent equilibrium geometry, with the goal of obtaining cross sections for electron impact excitation and dissociation. The polyatomic version of the UK molecular R -matrix codes was used to perform an initial configuration-interaction calculation on the doublet and quartet states of the C H 2 + ion. Subsequently, scattering calculations are performed to obtain electron impact electronic excitation and dissociation cross sections and, additionally, the bound states of the CH2 molecule and Feshbach resonances in the e - C H 2 + system. [ABSTRACT FROM AUTHOR]

Beryllium is being adopted for plasma facing walls in fusion reactors. This has led to the observation of emissions from the A 2Π state of beryllium hydride. Use of these emissions to monitor Be erosion requires electron impact excitation rates. Cross sections for electron impact vibrational excitation within the X 2Σ+ state and vibrationally resolved electronic excitation to the A 2Π state are reported for BeH, BeD and BeT. Electron collisions are studied at a range of internuclear separations using the UK molecular R-matrix (UKRmol+) codes. Electronic excitation is studied both within the Franck–Condon approximation and by explicit averaging of the T-matrix elements. It is found that (a) inclusion of the effect of higher partial waves using the Born approximation leads to significant increases in the cross sections and (b) the Franck–Condon approximation underestimates the importance of collisions for which the vibrational state changes during electronic excitation. [ABSTRACT FROM AUTHOR]