Experimental determination and calculation of the collision relaxation rates in the 5 2P1/2 and 5 2P3/2 levels of atomic iodine

Abstract

Pressure broadening of the hyperfine lines of the 2P1/2 –2P3/2 atomic iodine transition is analyzed from the emission line shapes. Collisions with Ar and O2 in the 0–100 Torr range were examined as well as pressure broadening due to I2 in the 0–15 Torr range. Pressure broadening coefficients α were determined: α (O2)=4.8 (3) MHz/Torr and α (Ar)=3.6 (3) MHz/Torr. In the case of I2, α (I2) is estimated to be (35±10) MHz/Torr in the 0–5 Torr range. In addition, pressure broadening coefficients were calculated using the impact approximation. In this approximation relaxation cross sections are calculated between hyperfine levels of the I atom. Estimates of the relaxation rates between the hyperfine levels of I(2P3/2) and I(2P1/2) are deduced from these results, for both elastic and inelastic processes. Experimental and theoretical results are in reasonable agreement.