Vibrational and electronic spectra of matrix-isolated nitrogen trimer radical and azide

Abstract

Static orientational factor for two-dimensional system with moments randomly distributed on cone with * = 58.4°.~15% in the deconvolutions. Moreover, the percent discrepancies are nearly constant, and the linearity of a plot similar to that in Figure 5 is hardly affected. Hence, our conclusion that the two-dimensional two-particle theory for (?(r) works well for all of the densities shown in Figure 5 is not sensitive to the model assumed for the orientational distribution of transition moments.Polarized fluorescence profiles obtained at higher chromophore densities than those shown in Table I show an interesting anomaly in that the fluorescence components /E, I_ do not converge together at long times. At 1511 X 10"6 chromophores/Á2, the two profiles intersect after ~1 ns, and I± decays more slowly than It at long times. At 2932 X 10"6 chromophores/Á2,1± remains below /E at all times, and the phenomenological decay times are markedly reduced. These ODRB densities are extremely large (the latter density corresponds to packing and average of ~16 chromophores per circle of radius R0 = 44.7 Á), and these polarization effects may result from excimer formation.We showed earlier8 that the three-dimensional two-particle theory of Huber et al.1 furnishes an accurate description of transport in solution for reduced concentrations up to ~3 in the absence of orientational correlation. Figure 5 indicates that the two-dimensional analogue (eq 3) of the Huber theory is valid for reduced ODRB densities CD up to ~5. This result is of particular interest, because density expansions of (?(Z) converge more slowly in systems of lower dimensionality. Hence, one may expect the demonstrated validity of the two-particle theory to be exhibited a fortieri in random three-dimensional systems; the system dimensionality does not pose fundamental problems in our understanding of singlet excitation transport.

FAR ULTRAVIOLET ABSORPTION SPECTRA OF N3AND N2+GENERATED BY ELECTRONS IMPACTING GASEOUS N2

“…This result is consistent with previous findings in N 2 matrices (Tian et al 1988;Zhou & Andrews 2000) and the amount of N 3 − was estimated to be fewer than 2.7 × 10 13 molecules cm −2 . In addition, green luminescence was observed during matrix deposition, indicating that N( 2 D) atoms were produced via radiolysis and subsequently relaxed to N( 4 S).…”

“…Time-dependent density functional theory (TD-DFT) was employed using the Gaussian 09 program (Frisch et al 2009) to calculate the vertical excitation energies of low-lying electronic states of N 3 . The geometry of the ground state X 2 Π g , maintaining D ∞h symmetry, and optimized with the PW91PW91 method (Perdew & Wang 1992;Perdew et al 1996) with the aug-cc-pV5Z basis set (Peterson et al 1994;Kendall et al 1992), yielded an N-N bond length of 1.184 Å, which is consistent with the experimental value of 1.182Ǻ (Tian et al 1988). Furthermore, the calculated vertical excitation energies and oscillator strengths of the first five doublet electronic transitions of N 3 from its ground electronic state are summarized in Table 3.…”

“…The single sharp band at 272.7 nm, with a FWHM of about 1.7 nm, was readily assigned to the transition A 2 Σ u + ← X 2 Π g of N 3 (Douglas & Jones 1965;Tian et al 1988;Wu et al 2013). Pure solid N 2 shows a series of intense absorption features commencing near 146 nm, associated with the Lyman-Birge-Hopfield (a 1 Π g ← X 1 Σ g + ) and Tanaka absorption (TA, w 1 Δ u ← X 1 Σ g + ) systems, which were discussed in our previous works .…”

A Theoretical Study of the Mechanism and Kinetics of F+N3 Reactions

“…The results at the CASSCFA C H T U N G T R E N N U N G (18,13) [38][39][40] Our calculated NN bond length (1.18531 ) is also close to the experimental value (1.18115 ). [41] 3.1.…”

The Photochemistry of [FeIIIN3(cyclam‐ac)]PF6 at 266 nm

“…It is very likely that this feature is due to the azide radical, the asymmetric stretch of which is located at 1658 cm À1 in a cryogenic nitrogen matrix. [14] To facilitate the assignment of the observed vibrational bands to the species invoked in Scheme 3, their harmonic vibrational frequencies were calculated using DFT as described in the section "Computational details". The computational data are also summarized in Table 1.…”