Elastic cross section data for precursor molecules used in low-temperature plasmas: Sn(CH₃)₄ and Ga(CH₃)₃

Tetramethyltin [Sn(CH 3 ) 4 ] and trimethylgallium [Ga(CH 3 ) 3 ] are important source molecules of Sn and Ga atoms which are used in manufacturing techniques involving low-temperature plasmas. Accurate numerical modeling of plasma environments requires a comprehensive set of electron scattering cross sections by these precursor molecules. Here, we report the elastic integral, differential, and momentum transfer cross sections for electron collisions with Sn(CH 3 ) 4 and Ga(CH 3 ) 3 for energies ranging from 0 to 30 eV. Our calculations were carried out with the Schwinger multichannel method implemented with pseudopotentials and considered two levels of approximation in our calculations, namely static-exchange and static-exchange plus polarization. We identified three shape resonances for Sn(CH 3 ) 4 and one clear low-lying resonance for Ga(CH 3 ) 3 . The low-energy behavior of the s -wave cross section and eigenphase was investigated and, for both molecules, we found evidence of a Ramsauer–Townsend (RT) minimum and a virtual state. Our results indicate that negative differential conductivity would occur in a gas composed of Sn(CH 3 ) 4 . On the other hand, this effect would be suppressed in a gas of Ga(CH 3 ) 3 due to an overlap between the position of the RT minimum and the shape resonance in the momentum-transfer cross section.