Knowledge Bank

The spectra of methyl iodide were determined in the range 2 to 15 microns for the vapor at $25\circ C$, the liquid at $25\circ$ and $-50\circ C$, and the solid at $-78\circ ,-196\circ$ and $-269\circ$C. Differences were observed in frequencies, intensities and band shapes resulting from changes in state and temperature. At the lowest temperatures band splitting could be resolved in the degenerate fundamentals as well as in the $1252cm-1$ nondegenerate fundamental.