Knowledge Bank

The far-infrared magnetic dipole transitions between fine-structure levels of the $23P$ ground states of oxygen and carbon atoms have been measured by laser magnetic resonance. The $J=2\to 1$ transition in oxygen was observed at 63.1 $\mu m$ ($\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CH3OH$) by generating the atoms in a discharge through $O2$ (1%) in helium. Using accurate g-factors determined by Radford and $Hughes(1)$ for these levels, a precise value for the $J=2\to 1$ splltting was obtained. By combining this result with the $J=1\to 0$ interval measured by Davits $etal(2)$ a precise analysis of the spin-orbit interactions and their effects on the magnetic behavior of the atom is possible. Both the $J=0\to 1$ transition, observed, at 570 $\mu m(CH3OH)$, and the $J=1\to 2$ transition, observed at 380.6 $\mu m(DCOOD)$, were detected for the first time in carbon atoms. C atoms were generated in a methane-fluorine atom flame. The splitting of the three magnetic components of the $J=1\to 2$ transition by the second-order Zeeman effect, which was not resolved for the 0 atom, was clearly observable. Similar measurements made for $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C$ allow Isotope shift and magnetic hyperfine effects to be calculated. This work also provides accurate frequencies which can be used in astronominal searches for these species.