GENERALIZEDVALENCE BOND AND CONFIGURATION INTERACTION CALCULATIONS ON THE LOW-LYING DOUBLET STATES OF $N^{+}_{2}$

$^{1}$A. E. Douglas, Can. J. Phys. 30, 302 (1952).Author Institution: California Institute of Technology; Cartwright, Aerospace CorporationFull GVB-CI calculations have been carried out on the low-lying doublet states of the nitrogen molecule-ion using the orbitals obtained from the calculations on the ground state of $N_{2}$. The calculated and experimental adiabatic excitation energies for the known states of $N^{+}_{2}$ are given in Table I. [FIGURE] Five new bound doublet electronic states of $N^{+}_{2}$ have been found within 12 eV of the $X^{2}\Sigma^{+}_{g}$ state. $A ^{2}-{\overline{\underline{o}}}_{g}$ state dissociating into $N(^{2}D) + N + (^{3}P)$, has been located 1.3 eV above the $D^{2}\Pi_{g}$ state. Two more $^{2}\Pi_{g}$ states have been found 2.0 and 3.6 eV above the $D^{2}\Pi_{g}$ state. In addition, two $^{2}\Delta_{u}$ states are found which lie close in energy and cross the $C^{2}\Sigma^{+}_{u}$ state near the minimum in its potential energy curve. A repulsive $^{2}\Sigma^{+}_{u}$ state ``crosses” the $C^{2}\Sigma^{+}_{u}$ state approximately 3 eV above its minimum. States of $^{2}\Sigma^{-}$ symmetry have not yet been studied. The anomalous shape of the potential energy curve of the $B^{2}\Sigma^{+}_{u}$ state as observed by $Douglas^{1}$ can be attributed to an avoided crossing of two potential curves, one arising from ionization of a 2s-orbital, the other from ionization of a $2p\sigma$-orbital. Accurate GVB and GVB-CI calculations are now being carried out on selected ion states