DIODE-LASER SPECTROSCOPIC STUDY OF THE O-2 A-BAND LINE-SHAPE PERTURBED BY N-2

The line shapes of the rovibrational components of the atmospheric A-b and of oxygen perturbed by nitrogen have been measured by a near infra red diode laser spectrometer using second harmonic detection technique . In the low pressure region, with the increase of perturber pressure the measured line widths show a very slow increase resulting from the combined effect of collisional narrowing and pressure broadening. When the total pressure exceeds 100 Torr, the line widths increase linearl y with the perturber pressure for a fixed partial pressure of oxygen. However, the line shape remains non-Voigt in nature. It is found that the narrowing produced by the perturber gas is less pronounced than th at produced by the self-induced collision. The simulation of line prof iles based on the soft collision Galatry model provides the coefficien ts of collisional narrowing and pressure broadening. (C) 1997 Elsevier Science B.V.