Process of dissociation of NH3 by electron impact in low-temperature plasma and its isotope effect

Abstract

Understanding the dissociative electron attachment (DEA) in low-temperature ammonia plasma is crucial for many technological applications, in particular, for alternative energy sources. However, theoretical modeling of this process has been challenging due to the complex interplay of electronic motion and multidimensional nuclear dynamics. This Letter presents a theoretical approach to investigate the process, applying it to the breakup of the ${\mathrm{NH}}_3$ molecule by low-energy electrons. The potential energy surface of the ${\mathrm{NH}}_3{}^{-}$ 5.5 eV resonant state is computed to elucidate the mechanism of the dissociative process. The cross section of DEA via the 5.5 eV resonance is then calculated for both ${\mathrm{NH}}_3$ and ${\mathrm{ND}}_3$. The positions of the peaks in both cross sections and the ratio between them are in excellent agreement with previous experiments. Our findings suggest that the developed theoretical model accurately describes the DEA process and could serve as a useful tool for providing DEA cross sections for other molecules to model low-temperature plasma.