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Ab initio calculations of the adiabatic potential curves and matrix elements of radial nonadiabatic coupling of the N2 molecule for the states related to dissociation limits I-V were performed. The most important spectral characteristics of the adiabatic states agreed well with the available experimental and theoretical data. The diabatic states were constructed. The diabatic quantum defects and radial matrix elements of the configuration interaction of the dissociative and Rydberg configurations whose states converge to the ground state X2Σg+ and the first electronically excited state A2Πu of the N2+ ion were calculated. The possibility of using the results for calculating the cross sections and rate constants of dissociative recombination and associative ionization within the framework of the multichannel quantum defect theory was discussed. [ABSTRACT FROM AUTHOR]

A method was developed for calculating the vibronic potential energy surfaces (PESs) of atmospheric complexes consisting of orbitally degenerate Rydberg nitrogen and oxygen molecules and the molecules of a neutral medium in the ground electronic state. The degenerate states are formed as a result of L-mixing in the D and E layers of the atmosphere during the periods of increased solar activity. The complexes are populated in the nonequilibrium two-temperature plasma and are responsible for the incoherent additional background radiation in the decimeter (microwave) and terahertz (IR) bands at an altitude of 80-110 km from the Earth's surface. To describe the interaction ofa weakly bound electron with a singly charged molecular ion and a neutral molecule ofa gas medium, the formalism of the multichannel quantum defect (MCD) theory was used. Quantum-chemical calculations of the dependences of the scattering lengths, polarizabilities, and quadru-pole moments of the main atmospheric molecules N2 and 02 on the interatomic distance were performed. The specific features of the behavior of vibronic PESs of Rydberg complexes for large values of the principal quantum number (n⪢) were analyzed. The vibronic PESs of orbitally degenerate states were constructed. They are necessary for determining the positions and shape of the vibronic minima of the L-mixing cross sections of the N2 and 02 Rydberg molecules in the D and E layers of the Earth's atmosphere, where the delay times of satellite positioning signals should be minimum. The possibility of "quantum chaos" appearing in the Rydberg complexes at sufficiently large n values and angular momenta of the weakly bound electron was noted. [ABSTRACT FROM AUTHOR]