Determination of the cross sections of the 2P1/2– 2P3/2 transition in iodine and bromine atoms

Laser atomic resonance spectroscopy was used in conjunction with iodine and bromine atomic lasers to determine the cross sections of the 5p^{5 2}P_1/2(F ' = 3) –5p^{5 2}P_3/2(F = 4) transition in the iodine atom and of the 4p^{5 2}P_1/2(F ' = 2) –4p^{5 2}P_3/2(F = 3) transition in the bromine atom. The cross sections under conditions of just the Doppler broadening were σ^D_3–4 = (1.3±0.2)×10 ^–17 cm² and σ^D_2–3 (1.0 ± 0.2) × 10 ^–17 cm² at 300 K, in agreement with the published calculations. At 1 kK the broadening coefficients were determined for the transition in the iodine atom in O₂, N₂ , I₂ gases (1.7 × 10¹⁵ cm ^–2 · Torr ^–1) and in Ar, CO₂ (1.3 ×10¹⁵ cm ^–2 ·Torr ^–1), as well as for the transition in the bromine atom in Br₂ gas (4.6×10¹⁵ cm ^–2 ·Torr ^–1).