Excitation of Even Triplet Levels of $\mathrm{LaII}$ in $\text{e}$–$\text{La}$ Collisions

The excitation of radiative transitions from even triplet levels of $\mathrm{LaII}$ is investigated by the method of extended crossing beams with detection of optical signal from the region of crossing. The optical excitation functions are measured for $27$ spectral lines in the electron energy range of $0$–$200$ eV. Based on the results of measurements, the total excitation cross sections are calculated for $34$ energy levels of a singly charged lanthanum ion at the electron energy of $30$ eV.