Photoelectron spectroscopy of the negative cluster ions NO−(N2O)n=1,2

Abstract

We have recorded the photoelectron (photodetachment) spectra of the gas-phase negative cluster ions NO−(N2 O)1 and NO−(N2 O)2 using 2.540 eV photons. Both spectra exhibit structured photoelectron spectral patterns which strongly resemble that of free NO−, but which are shifted to successively lower electron kinetic energies with their individual peaks broadened. Each of these spectra is interpreted in terms of a largely intact NO−subion which is solvated and stabilized by nitrous oxide. For both NO−(N2 O)1 and NO−(N2 O)2, the ion–solvent dissociation energies for the loss of single N2 O solvent molecules were determined to be ∼0.2 eV. Electron affinities were also determined and found to increase with cluster size. The localization of the cluster ion’s excess negative charge onto its nitric oxide rather than its nitrous oxide subunit is discussed in terms of kinetic factors and a possible barrier between the two forms of the solvated ion.

Kinetic Stability and Propellant Performance of Green Energetic Materials

“…It is important to note that 13 has a bonding enthalpy of 4.3 kcal mol À1 , relative to free NO and N 2 O À (9). This value corresponds well with the experimental bond strength of 0.2 eV (4.6 kcal mol À1 ), presented by Coe et al [15] As mentioned earlier, the true kinetics for decomposition of the trinitrogen dioxide anion is complicated by the proximity of different spin states. Equation (2) (2!…”

“…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.…”

“…[25,[28][29][30] Other pentazole compounds are also known. Hammerl and Klapçtke have, for instance, shown the existence of tetrazolylpentazole by using low-temperature 15 N/ 1 H NMR spectroscopy. [31] The stability of tetrazolylpentazole and its corresponding anion pentazolyltetrazolate was calculated to be 15-16 and 21-22 kcal mol À1 , respectively, using B3PW91 and MP2 calculations, [31] and later to be 11.4 and 17.7 kcal mol À1 , respectively, using CCSD(T) calculations.…”

“…[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 ). [15] Despite its apparent stability in the gas phase, no attempts to chemically synthesize 2 have been reported, and no detection or characterization of the ion in solution is known.…”

Collisional electron detachment from NO− by rare gases

“…As mentioned above, CO2 and N2O are known to associate with NO~ at low temperature, implying a long-lived complex and therefore the concept of a purely repulsive collision does not apply [2]. The binding energy of N2O with N0~ has been reported to be 0.2 eV [30] in which case the electron detachment would be exothermic on collision and it is well established that non-adiabatic processes readily occur in complexes [31]. Similar situations may apply to the other molecular species, e.g., the associative detachment NO" -(-NO = ONNO -I-e~ is 43 meV [32] exothermic but does not occur [1].…”