Transition probability and collision broadening of the 13-μm transition of atomic iodine

Abstract

We have made direct absorption measurements of the transition probability and collision broadening of the 1.3-μm 2P1/2 → 2P3/2 transition of atomic iodine. Atomic iodine was generated in heated iodine vapor, and the spectrum was obtained with a Fourier-transform spectrometer. A transition probability was measured that corresponds to a 2P1/2 radiative lifetime of 125 msec. Broadening coefficients of 1.4, 1.7, 3.1, and 1.3 MHz/Torr at 1000 K were found for argon, oxygen, molecular iodine, and atomic iodine, respectively. The intensity of the (2, 4) forbidden electric-quadrupole line was measured and yielded the ratio of electric-quadrupole to magnetic-dipole transition probability of 2.7 × 10−3. Molecular absorption spectra of IO and SiI were seen in high-temperature spectra of a quartz cell containing an I2/O2 mixture.