Mass Ratio of the Boron Isotopes from the Spectrum of BO

Wave number data. New measurements are made of the rotational structure of the $\alpha$ bands of BO, and the wave numbers of the lines in the ${}_{}{}^2{}_{}{}^{}\Pi _{\frac{1}{2}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}\Sigma$ component up to about $J=20\mathrm{}$ are tabulated for the (0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (3, 0), and (4, 0) bands of both the ${\mathrm{B}}^{11}$O and ${\mathrm{B}}^{10}$O systems. The ${}_{}{}^2{}_{}{}^{}\Pi _{\frac{1}{2}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}\Sigma$ component of (5, 0) is also measured for ${\mathrm{B}}^{11}$O and the ${}_{}{}^2{}_{}{}^{}\Pi _{\frac{3}{2}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}\Sigma$ component of (1, 0) for ${\mathrm{B}}^{11}$O and ${\mathrm{B}}^{10}$O.