Author Institution: Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands; Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, AustraliaThe nitrogen molecule is a long-studied and difficult problem in molecular spectroscopy, and many important details of its interaction with radiation remain unexplained. A principal problem of continuing interest concerns the resonant photoabsorption and resultant predissociation of N2 when exposed to extreme-ultraviolet radiation. \vspace{2ex} A model of the relevant excited states of N2 has been developed in order to quantify their interactions and reproduce photoabsorption and photodissociation cross sections between 100\,000 and 118\,500\,cm−1 (100 and 84\,nm). This solves the radial Schrodinger equation within a coupled-channels formulation for new diabatic potential-energy curves, homogeneous and heterogeneous state mixing, and electronic transition moments for the optically allowed transitions. The accidental predissociation of 1Πu states between 100000 and 112\,500\,cm−1 has been quantitatively modelled by spin-orbit coupling these to a set of 3Πu and 3Σu+ states which includes unbound members. \vspace{2ex} Following reference to a large experimental database, the model is both accurate and comprehensive and may be used to simulate synthetic cross sections for any temperature or isotopologue. These are suitable for use in high-resolution photochemical models of atmospheric and astrophysical environments
