Knowledge Bank

The method of Laser-Induced-Reactions (LIR), which is described in detail in Schlemmer et al. 2002 nderline{\textbf{117}}(2068-2075), 2002}, is used to obtain high-resolution infrared spectra of molecular ions. % Here, the endothermic reaction C$2$H$\mathrm{2+}$~+~H$2 \to$~C$2$H$\mathrm{3+}$~+~H is promoted by ro-vibrational excitation of the parent ion. A spectrum of the $\nu 3$ stretching vibration of C$2$H$\mathrm{2+}$ is recorded by variation of the wavelength of a home-build OPO (Optical Parametric Oscillator) operating in the 3 micron region. % The experiments are carried out in a low temperature 22-pole ion trap where several hundred cold, mass selected parent ions are stored. Typical linewidths of the action spectra are 3~$\times$~10$\mathrm{<mrow\; data-mjx-texclass="ORD">-3</mrow>}$~cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. First spectra for C$2$H$\mathrm{2+}$ and their analysis will be presented. Other possible applications of LIR spectroscopy will be discussed.