COLLISIONAL SHIFT AND BROADENING OF IODINE SPECTRAL-LINES IN AIR NEAR543 NM

The collisional processes that influence the absorption of monochromat ic light by iodine in air have been investigated. Measurements were ma de in both a static cell and an underexpanded jet flow over the range of properties encountered in typical compressible-flow aerodynamic app lications. Experimentally measured values of the collisional shift and broadening coefficients were 0.058 +/- 0.004 and 0.53 +/- 0.010 GHz K -0.7/torr, respectively. The measured shift value showed reasonable ag reement with theoretical calculations based on Lindholm-Foley collisio nal theory for a simple dispersive potential. The measured collisional broadening showed less favorable agreement with the calculated value.