Knowledge Bank

We have investigated the resonant Magnetic Rotation Spectrum of the weak A $^{3}\Pi_{1u} - $X $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma g+$ electronic band of isotopically pure $\mathrm{<mrow\; data-mjx-texclass="ORD">79</mrow>}Br2$. With absorption $techniques1$, overlap with the very strong (B $^{3}\Pi_{a+u} - $X $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma g+$ electronic band at all wavelengths makes the weak A-X system particularly difficult to study. On the other hand, the magnetic rotation technique has strongly suppressed the overlapping B-X electronic band, and the resulting Magnetic Rotation Spectrum of the weak A-X band had a signal to noise ratio of at least 350 on a typical line. This technique is extremely sensitive to low J lines which are otherwise very difficult to observe at room temperature.