Diode laser spectroscopy of ammonia at 760nm

Abstract: A tunable diode laser spectrometer has been employed to examine the unknown overtone absorption lines of around (760nm). The spectrometer sources are commercially available heterostructure AlGaAs tunable diode lasers operating in the “free-running” mode. The detection of the lines has been possible by the use of the wavelength modulation spectroscopy and the second harmonic detection technique. A special algorithm has been used in order to fit the highly modulated absorption lines. The weakest observed resonances have absorption cross sections on the order of ≃/molecule or ≃/amagat. For some of the more intense lines self-, air-, -, He- and -broadening coefficients have been obtained at room temperature and also some shifting coefficients have been measured. [Copyright &y& Elsevier]