Knowledge Bank

From the analysis of the A-X and $A\prime -X$ systems of the $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}N80$ Se and $15N80Sc$, an anomalous A-doubling of the $X2\Pi$ state has been observed. This is due to an interaction between the nearly degenerate $v+1$ and vibrational levels of the $X2\Pi 1/2$ and $X2\Pi 3/2$ substates. The ‘‘s-uncoupling’’ operator which is nonzero for $\Delta V=1$, is shown to be responsible in part for the mixing. The interaction constant, obtained by a least squares fit of the observed term values, is compared with the calculated one.