Electronic states of $Na_{3}$ and $Na_{1}$ : Calculated PE surfaces and molecular structures

This work is expected to give precise energetic characteristics and electronic structures for the lowest states of $Na_{3}^{+}$ and $Na_{3}^{+}$ and $Na_{3}$. The spectroscopic implications of the calculated potential energy curves will be discussed in light of recent experimental observations.Author Institution: Laboratoire de Chemie Quantique, Universit\'{e} L. Pasteur; Laboratoire de Spectrometrje el Moleculaire, Universit\'{e} de Lyon l (Bat. 205)All electronic states of $Na_{j}^{+}$ dissocrating into $2Na(3s) + Na^{+}$ and some lowest states dissociating into $Na(3s) + Na(3p) + Na^{+}$ are calculated in full valence CI using a flexible basis set. D*, of the ground state $^{1}A_{1}$ with respect to $Na_{2}(X^{1}\sigma^{+}) + Na^{+}$ is 1.376 eV. A strong Jahn-Teller effect for the first excited state $^{2}E$ leads to a linear $^{3}\Sigma^{+}$ and an acute-angle 3A1 geometries. These states are stable with respect to dissociation into $Na_{2}(X^{1}\Sigma^{+}) + Na^{+}$. Other three states are repulsive. Among the molecular states which can be made from $Na(3s) + Na(3p) + Na^{+}$, only the $^{1}A_{2}$ state is quite stable $(D, = 0.958el)$ with respect to dissociation into $Na_{2}(a^{3}\Pi_{u})+Na^{+}$. The two Jahn-Teller partner states of $(2)E$ are very weakly bound. The lowest states of Na1 are also calculated in full VCI. The ground state $(^{2}B_{5})$ is stable by 0.290 eV with respect to dissociation into $Na_{2}(X^{1}\Sigma_{g}^{+}) + Na(3s)$. The $^{2}B_{1}$ state is only 0.021 eV lower than the $^{2}A_{1}$ state and the comc intersection $(2E)$ lies 0.093 eV higher than the $^{2}B_{1}$ state. The (dynamic) Jahn-Teller character of the lowest states and their bonding nature are discussed