Diode laser spectroscopy of methyl chloride overtones at 850-860 nm

- Methyl chloride overtone absorption lines have been observed at 850-860 nm.
- Laser diodes sources and the frequency modulation technique permit fine spectroscopy.
- Absorption cross sections in the range of 10−26 cm2/molecule have been detected.
- A pressure self-broadening coefficient have been collected for one line.

By using a tunable diode laser (TDL) spectrometer 156 CH3Cl overtone absorption lines have been detected in the range between 11,590 and 11,760 cm−1 (8500-8625 Å). Their strengths range around 10−26-10−27cm/molecule and have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation spectroscopy (WMS) and the 2nd harmonic (2f) detection techniques. For one line the self-broadening coefficient has been obtained.