Knowledge Bank

The absorption and emission spectra of silicon difluoride and germanium difluoride have been observed in the vacuum ultraviolet region at wave-lengths shorter than 1800 \AA at a dispersion of 3.75 \AA/mm. The spectra are assigned as resulting from the transition B $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}B2-X1A1$. The observed bands in absorption are believed to represent a sequence in the ground and upper state bending frequencies and a progression in the upper state symmetric stretching frequency. The observed bands in emission are assigned as a progression in the lower state symmetric stretching frequency.