Precise measurements of hyperfine components in the spectrum of molecular iodine

Absolute wave numbers with a typical uncertainty of 1 MHz (95% confidence) were measured for 102 hyperfine-structure components of I-127(2). The data cover the range 560 to 656 nm with no gaps larger than The spectra were observed by use of Doppler-free frequency-modulation spectroscopy with a tunable The laser was locked to selected iodine components, and its wave number was measured with a high-precision Fabry-Perot wavemeter. The accuracy of the results is confirmed by the good agreement of nine of the lines with previous results from other laboratories. These measurements provide a well-distributed set of precise reference lines for this spectral region.