PRESSURE BROADENING OF THE ATOMIC IODINE $5^{2}p_{1/2} - 5^{2}p_{3/2}$ TRANSITION

Author Institution: Laboratioire de Spectrometrie Ionique et Moleculaire; Laboratioire Aime Cotton, CNRS IIThe presser broadening of the hyperfine lines of the $^{2}p_{1/2} - ^{2}p_{3/2}$ atornic iodine transition is of importance in the chemically pumped iodine laser. The hyperfine lines are observed in emission with a high resolution Fourier Transform spectrometer after dissciation of $I_{2}$ by the $4965 n m Ar^{4}$ lines. Pressure broadening of 1.95 MHz/torr, 39 MHz/torr and 193 MHz/torr were observed by colilisiton with Argon Oxygen and Iodine respectively. We have tried to caluculate theoretically these enlargements by a semi-classical method. Relaxation cross-sections are calculated between hyperfine levels of the I atom, in the first order Born approximation. The intraction potential is a second order long-range potential, described as a multipolar expansion between $O_{2}$. Ar or $I_{2}$ and I atom and calculated from molecular or atomic polarlsabilities