Knowledge Bank

The $B3\Sigma u-$ state of molecular oxygen (the upper state of the Schumann Rung band system) is predissociated by several repulsive continuum states including the $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Pi u,3\Pi u,5\Pi u$ and $231\Sigma u$ states. In an extension of the work of Julienne and $Krauss1$, who first showed that the $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi u$ state is the dominant perturbative state, we have determined an empirical representation for the $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Pi u$ state which yields a smooth deperturbation in the second vibrational energy differences of the three isotopic molecules $\mathrm{<mrow\; data-mjx-texclass="ORD">16</mrow>}O2,16O18O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O2$. The $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Pi u$ state is found to cross the $B3\Sigma u-$ state at $1.880\backslash AA$ with a slope at the crossing point of $40000cm-1\backslash AA-1$ and the coupling strength between the $\mathrm{<mrow\; data-mjx-texclass="ORD">5</mrow>}\Pi u$ and $B3\Sigma u-$ states is $65cm-1$.