Dissociative Photodetachment Dynamics of Isomeric Forms of N₃O₂^-

Abstract

The dissociative photodetachment of N3O2 - at 532, 355, and 266 nm has been studied using coincident photoelectron and photofragment translational spectroscopy in a fast-ion beam. The photoelectron spectra confirm previous experimental evidence for a weakly perturbed NO-(N2O) complex and show for the first time a broad continuum at large electron-binding energies. Translational energy release spectra exhibit both low- and high-energy-release channels, indicating that two regions of the NO−N2O neutral potential energy surface with very different intermolecular repulsion are accessed. Photoelectron−photofragment coincidence data confirm that the high translational energy release events are correlated with the continuum in the photoelectron spectrum. These dissociative photodetachment dynamics are consistent with the existence of two isomeric species, an ion−dipole complex with the charge localized on the NO moiety and a molecular anion with an estimated stability of 2.0 ± 0.2 eV relative to NO + N2O + e-.

Kinetic Stability and Propellant Performance of Green Energetic Materials

“…We can conclude that, in contrary to several other computational studies on the matter of trinitrogen dioxide, our calculations offer a strong complement to the experimental work by Resat et al, [13] Torchia et al, [14] and Coe et al [15] The barrier for decomposition in the gas phase is close to 30 kcal mol À1 . Larger as well as significantly smaller experimental bond strengths can be explained using different rotational conformers, loose complexes, and a strong photon absorption at 271 nm.…”

“…[13] They concluded that this value may be taken as a measure of the stability of 2 if it is assumed that some of the NO + N 2 O products are produced with no internal excitation, and that the parent N 3 O 2 À molecule is cold. However, their measured value for Equation (3) is considerably higher than our computed value of 27.0 kcal mol À1 for the same process.…”

“…Equation (13) has been shown to be applicable to a wide range of 1:1 salts, and the Gutowski approach has recently been deemed the theoretical method of choice for estimating solid-phase heats of formation for energetic salts. [63] Figure 8.…”

“…[11] Its existence in the gas phase has since been corroborated by several groups. [12][13][14] The stability of 2, relative to NO + N 2 O + e À , has been measured to be (2.0 AE 0.2) eV ((46 AE 4.6) kcal mol À1 ) using coincident photoelectron and photofragment translational spectroscopy. [13] Collision-induced dissociation studies also support the existence of an isomer with an estimated stability of (0.76 AE 0.1) eV ((18 AE 2.3) kcal mol À1 ).…”

“…[12][13][14] The stability of 2, relative to NO + N 2 O + e À , has been measured to be (2.0 AE 0.2) eV ((46 AE 4.6) kcal mol À1 ) using coincident photoelectron and photofragment translational spectroscopy. [13] Collision-induced dissociation studies also support the existence of an isomer with an estimated stability of (0.76 AE 0.1) eV ((18 AE 2.3) kcal mol À1 ). [14] There is also evidence to suggest an isomer with a bond strength of approximately 1.3 eV (30 kcal mol À1 ), [14] as well as a weakly bound [NO-N 2 O] cluster bonded by approximately 0.2 eV (5 kcal mol À1 ).…”