Simulation of the emission spectrum of $\mathrm{SiH}$ $(\mathrm{A}^2\Delta\to\mathrm{X}^2\Pi)$ and measurement of the rotational temperature of the $\mathrm{A}^2\Delta$ state in an electron-beam plasma

The $0$–$0$ band emission spectrum of the $\mathrm{A}^2\Delta\to\mathrm{X}^2\Pi$ transition of the $\mathrm{SiH}$ molecule was modeled numerically. The results obtained agree well with known calculated and experimental data. The rotational temperature of the $\mathrm{A}^2\Delta$ state of $\mathrm{SiH}$ in a free stream of pure monosilane $(\mathrm{SiH}_4)$ and in a mixture with helium $(\mathrm{He} + \mathrm{SiH}_4)$ activated by an electron beam is determined by comparing calculated and experimental spectra. The assumption that the emission of $\mathrm{SiH}$ results from dissociative excitation of $\mathrm{SiH}_4$ by electron impact is confirmed. Rotational temperatures for various monosilane concentrations and distances from the nozzle are given. The spectra obtained exhibit the emission of silicon ions at wavelengths of $412.807$ and $413.089$ nm.