Knowledge Bank

The wavelengths of about 200 lines of the $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C18O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C18O$ lasers have been measured, using an infrared spectrometer, with an accuracy letter than $0.01cm-1$. In addition, about 40 beat frequencies between $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C16O,13C16O,12C18O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C18O$ laser lines have been measured, using an optical heterodyne technique, with an accuracy of about 10 MHz. These data have been combined with measurements already in the literature (see for $example1$) in a least squares fit in which all the isotopic species have been dealt with at the same time. The resulting single set of Dunham coefficients, together with some mass scaling $factors,2$ have been used to calculate CO laser line frequencies. We are especially interested in improving the relative accuracy of the frequencies of the various isotopes in the lower frequency region ($1600-1450cm-1$) of laser operation; this is important for the spectroscopic applications (e.g. laser; magnetic resonance, laser Stark spectroscopy) of the CO laser.