Heterodyne frequency measurements of ^13CO_2 laser hot band transitions

The frequencies of twenty-eight lines in the P-branch of the 01(1)1-[11(1)0,03(1)0](I) band of (13)C(16)O(2), observed in laser emission, and three lines in the R-branch, observed in absorption with a diode laser, have been carefully measured with stabilized CO(2) lasers. A significant improvement in the ro-vibrational constants has been obtained from a least squares fit to these data. The laser lines stabilized by saturated absorption techniques provide convenient, accurate (uncertainty <0.1 MHz) frequency references near 11.7 microm.