Assignment in the near-threshold absorption spectrum of N2

The absorption spectrum of N(2), just above the first ionization limit, in the region between 125,750 and 126,600 cm(-1), is dominated by two broad features which have the appearance of the towers of a "cathedral." Recently, this energy region has been measured by Sommavilla et al. J. Phys. B 35, 3901 (2002)] with a resolution of 0.04 cm(-1) and an assignment for one of these two bands has been suggested. In order to discuss this assignment, we have solved the coupled-channel Schr?dinger equation with the parameters of Spelsberg and Meyer above the v=28 level of the b(') (1)Sigma(u)(+) state for determining the high levels of b('). Furthermore, we evaluate the autoionization widths and the rotational structure of the different possible assignments. Finally, we propose as assignment for the second tower of the cathedral the Rydberg state (A (2)Pi(u)v(+)=1)3(')d(')sigma(g) (1)Pi(u).