Terahertz absorption spectra of nitromethane

Nitromethane, with its heavy frame and internal rotator, readily evaporates into the atmosphere making it an ideal candidate for remote sensing. Here we present the absorption spectra of gas-phase nitromethane between 9 and 50 cm −1. Measurements were taken using a Bruker IFS 66v Fourier transform far-infrared (FTIR) spectrometer at a resolution of 0.12 cm −1 (0.0036 THz) from 9 to 40 cm −1 and a Bruker Vertex 80v FTIR spectrometer with a resolution of 0.0075 cm −1 (0.00226 THz) from 10 to 50 cm −1. The absorption spectra were measured at multiple pathlengths ranging from 2 to 6 m. These measurements were used to calculate the absorption coefficient of nitromethane as a function of wavenumber. ► Absorption spectra of nitromethane. Absorption spectra of pressure-broadened nitromethane. ► Absorption coefficients calculated for nitromethane and pressure-broadened nitromethane. ► Minimum detectable limit established for nitromethane.