Diode laser spectroscopy of methyl fluoride overtones at 850 nm

- Many methyl fluoride absorption lines have been observed at 845-865 nm.
- Laser diodes sources and the frequency modulation technique permit fine spectroscopy.
- Absorption cross sections as low as 1×10−26 cm2/molecule have been detected.
- Pressure broadening and shift coefficients have collected for the more intense lines.

One hundred fifty-six 12CH3F overtone absorption lines, comprised between 11 545 and 11 836 cm−1, have been observed by using a tunable diode laser (TDL) spectrometer. Their intensities range around 10−26 cm/molecule and have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation (WM) and the 2nd harmonic (2f) detection techniques. Self-broadening coefficients and line strengths have been measured at room temperature for seven of the strongest transitions, while air-broadening coefficients have been obtained for two lines. In addition, self- and air-collisional shifts have been measured for the 11 564.25 cm−1 transition.