High precision saturation spectroscopy of 127I2 with argon lasers at 5 145 Å and 5 017 Å : I — Main resonances

Abstract

We present results on the hyperfine spectroscopy of 127I 2 obtained with argon lasers. We describe our saturated absorption or dispersion spectrometer and we discuss the pressure dependence of the saturation line shapes. At 5 145 Å we have measured the frequency differences between the main resonances of the 43-0 P(13) and R(15) hyperfine manifolds with a 200 Hz standard deviation and obtained a theoretical fit with a standard deviation of the order of 1.5 kHz. The two sets of hyperfine constants for P(13), and R(15) are consistent. The results of Foth and Spieweck are confirmed for the 58-1 R(98) line at 5 145 Å and we make a first determination of the constants d' and δ' of the 62-0 R(26) line at 5 017 Å. The variation of these constants near the dissociation limit is interpreted as a demonstration of a mixing of u and g states. The stability of argon lasers slaved to iodine peaks is illustrated and their metrological applications are outlined