Absolute frequency measurements and comparisons in iodine at 735 nm and 772 nm

We report frequency measurements at the rovibronic transition P(42)1-14 (772 nm) and R(114)2-11 (735 nm) from the electronic transition of the iodine molecule ¹²⁷I₂ with the help of a frequency comb as a reference. By using Doppler-free saturation spectroscopy a frequency precision in the 7 × 10⁻¹⁰ region is reached and two iodine cells both operated at 550-600 °C are compared. To relate our results to other measurements, the absolute transition frequency of the hyperfine structure line P(148)1-14 a₁ at 780 nm with an already known transition frequency was also determined.