Experimental verification of strong rotational dependence of fluorescence and predissociation yield in the b 1Πu(v = 1) level of 14N2

The spin-forbidden vacuum-ultraviolet absorption spectrum of 14N15N

Photoabsorption spectra of ¹⁴N¹⁵N were recorded at high resolution with a vacuum-ultraviolet Fourier-transform spectrometer fed by synchrotron radiation in the range of 81-100 nm. The combination of high column density (3 × 10¹⁷ cm^-2) and low temperature (98 K) allowed for the recording of weak spin-forbidden absorption bands' exciting levels of triplet character. The triplet states borrow intensity from ¹Π_u states of Rydberg and valence character while causing their predissociation. New predissociation linewidths and molecular constants are obtained for the states C³Π_u(v = 7, 8, 14, 15, 16, 21), G³Π_u(v = 0, 1, 4), and F³Π_u(v = 0). The positions and widths of these levels are shown to be well-predicted by a coupled-Schrödinger equation model with empirical parameters based on experimental data on ¹⁴N₂ and ¹⁵N₂ triplet levels.

Observation of new Rydberg series in the many-electron transition region of N2

Fluorescence excitation spectra produced through photoexcitation of N(2) using synchrotron radiation in the spectral region between 50 and 62.5 nm have been obtained with a resolution of 0.004 nm. A broadband detector (in the 115-180 nm region) was employed to monitor fluorescence originated from neutral excited atomic nitrogen fragments which are produced through direct dissociation processes and predissociation from the well-known many-electron excited Rydberg states. We have identified a new Rydberg series (2 (2)Π(g)) 4sσ, a better resolved Rydberg (D (2)Π(g)) npσ series, and also the prominent Codling series converging to the D (2)Π(g), and C (2)Σ(u)(+) states of N(2)(+), respectively. By normalizing our relative fluorescence intensities to previously measured absolute fluorescence cross-section data we obtain the cross-section data of undispersed fluorescence in the 115-180 nm region. The fluorescence quantum yields for the present photodissociative excitation processes are found to be less than 0.05. The present results may provide important data for our understanding of competitions among the various decay channels of the many-electron transition states of N(2).