Knowledge Bank

A discussion is provided for the explanation of the five salellite bands observed in the very for wings of the self-broadened D1 and D2 cesium resonance lines. It seems that the Van der Waals type interaction, avoided crossings and exchange interaction contribute to a bending downwards of initially repulsive resonance interaction curves $2g,1g,1u,0g-$ and $0g-+$. This results in the formation of the five maxima, which correspond to the five observed satellites in the far quasistatic wings. One of the maxima is identified as a hump in the $B1\Pi u$ (or $1u$) potential curve with the relevant height above $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}P3/2+2S1/2$ level of about $250cm-1$, which well agrees with the height of about $254cm-1$ obtained by the extrapolation procedure from the $x1\Sigma g+-B1\Pi u$ bands of the $Cs2$ molecule by Kusch and Hessel. Possible implications of the present model Lo other alkali dimers will be discussed.