Oscillator strengths and line widths of dipole-allowed transitions in [sup 14]N[sub 2] between 86.0 and 89.7 nm

Vacuum ultraviolet photoexcitation and photofragment spectroscopic studies of 14N15N between 109000 and 117500 cm-1

In this study, we employed a newly built time-slice velocity-map ion imaging setup, equipped with two tunable vacuum ultraviolet (VUV) laser sources, to obtain the first comprehensive high-resolution photoexcitation and photofragment excitation spectra of ¹⁴N¹⁵N in the VUV photon energy range 109 000-117 500 cm^-1. The spectroscopic simulation program PGOPHER was used to analyze the rotationally resolved spectra. Band origins, rotational constants, and isotope shifts compared with those of ¹⁴N₂ have been obtained for 31 electric-dipole-allowed vibrational states of ¹⁴N¹⁵N in the aforementioned energy range. These spectroscopic parameters are found to depend on the vibrational quantum number irregularly. Systematic perturbations of the rotational transition energies and predissociation rates within individual absorption bands have also been observed. These are proved to be caused by the strong homogeneous interactions between the valence b'¹Σ_u ⁺ state and the Rydberg c_n ^{' 1}Σ_u ⁺ states, and between the valence b¹Π_u states and the Rydberg o₃ ¹Π_u states. Heterogeneous interactions between the Rydberg c_n ¹Π_u states and c_n ^{' 1}Σ_u ⁺ states also play an important role.

High-resolution Fourier-transform extreme ultraviolet photoabsorption spectroscopy of 14N15N

The first comprehensive high-resolution photoabsorption spectrum of (14)N(15)N has been recorded using the Fourier-transform spectrometer attached to the Desirs beamline at the Soleil synchrotron. Observations are made in the extreme ultraviolet and span 100 000-109 000 cm(-1) (100-91.7 nm). The observed absorption lines have been assigned to 25 bands and reduced to a set of transition energies, f values, and linewidths. This analysis has verified the predictions of a theoretical model of N(2) that simulates its photoabsorption and photodissociation cross section by solution of an isotopomer independent formulation of the coupled-channel Schrödinger equation. The mass dependence of predissociation linewidths and oscillator strengths is clearly evident and many local perturbations of transition energies, strengths, and widths within individual rotational series have been observed.