State-selected vibrational relaxation rates for highly vibrationally excited oxygen molecules

Hernández, R. Pomés; Toumi, Ralf; Clary, David C.

doi:10.1063/1.468770

Cited by 71 publications

(51 citation statements)

References 37 publications

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“…The two calculations used the same theoretical method but different intermolecular potential energy surfaces. In addition, Hernandez et al [24] performed ab initio calculations of O 2 -O 2 V-V rates and their values agreed well with experimental results for v greater than eight, but rate coefficients for lower vibrational levels (v < 8) were not reported.…”

Section: Kinetic Modeling and Rate Inferencesupporting

confidence: 56%

Stimulated Raman scattering measurements of V–V transfer in oxygen

2006

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Section: Kinetic Modeling and Rate Inferencesupporting

confidence: 56%

Stimulated Raman scattering measurements of V–V transfer in oxygen

2006

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“…For the singlet ground state, values for the well depth in the D 2h configuration ranging from 0.29 [17] to 2.36 kJ ? mol 21 [18] are reported. This report presents the first detailed experimental characterization of the interactions in the gas phase O 2 -O 2 dimer, including an assessment of the spin-spin coupling, from molecular beam scattering studies.…”

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confidence: 99%

Quantum Interference Scattering of Aligned Molecules: Bonding inO4and Role of Spin Coupling

et al. 1999

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Molecular beam experiments on collisions between oxygen molecules were performed at low energy and high angular resolution to permit observation of the "glory" interference effect. A novel technique for aligning the rotational angular momentum of the colliding molecules is exploited. Analysis of total scattering cross section data yields for the O 2 -O 2 bond an energy of 1.65 6 0.08 kJ ? mol 21 for the most stable configuration (parallel molecules) at a distance of 0.356 6 0.007 nm. These results indicate that most of the bonding in the dimer comes from electrostatic (van der Waals) forces but chemical (spin-spin) contributions are not negligible. [S0031-9007(98) The interactions of molecular oxygen are of vital importance in a number of fields such as combustion and, particularly, atmospheric physics and chemistry. Despite continuing efforts, some of the processes linked to the release and recombination of oxygen in its various forms are still far from being properly understood. Among these, those involving the oxygen dimer ͑O 2 ͒ 2 are particularly interesting both for the peculiar nature of the bond [1,2] and for their relation to the atmospheric ozone and atomic oxygen balance, through the highly endothermic reaction [10]. For the latter, three different phases, two of which are paramagnetic, are known but their modeling is not fully understood. Finally, spectra of the dimers show several weak absorption bands [11]. They are observed in the atmosphere and in oxygen under pressure or as a liquid and their assignment is far from complete. Some occur in the same wavelength range as the Chappuis bands of ozone, hence affecting measurements of stratospheric ozone [11]. The intermolecular potential in the oxygen dimer continues to pose a challenge to the theory of weak chemical bonds, beyond van der Waals forces. Indeed, because of the open shell nature of the oxygen molecules in their 3 S 2 g ground electronic state, the interaction in the dimer depends not only on the intermolecular distance and on the relative orientation between two molecules, but also on the coupling of their spins [12]. This originates a singlet ground potential energy surface and two excited ones, of triplet and quintet character.Ewing et al. [13] were the first to reveal clearly the presence of ͑O 2 ͒ 2 dimers in the gas phase, by spectroscopic studies at low temperature in the IR and visible range. From the analysis of the collision induced absorption spectrum they concluded that the dimer, a floppy molecule, is stabilized both in the ground and the excited electronic state [dissociating to O 2 ͑ 1 D͒ 1 O 2 ͑ 1 D͒] by a weak bond of van der Waals nature with well depths of 1.0 and 0.6 kJ ? mol 21 , respectively. They also give an equilibrium distance of ϳ0.35 nm tentatively associated with a parallel (H-like) geometry but provide no information on spin coupling and on the dependence of the interaction on the mutual orientation of the molecules.As for the magnetic properties of oxygen dimers in the gas phase an early study [14] of Stern-...

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“…Now, the matrix in [12] above plays the same role as that in [3], Section 2, and the expression of T É eq analogous to…”

Section: By Forcing the Constraints {Qљmentioning

confidence: 96%

“…For calculating the determinant, let us rewrite the matrix in [3], which is for free motion, in the following form (note that the blocks in (i Å 1, . .…”

Section: Hamiltonians For Rigidlymentioning

confidence: 99%

“…However, the corresponding exact kinetic energy tion of the low-lying bands of the infrared spectra of four-operator cannot be straightforwardly written, even if the opatom molecules described in terms of curvilinear internal erator for the constraint-free system is known. Indeed comcoordinates (2), (ii) nearly ab initio dynamical calculations pelling model constraints modify the metric of the configurafor bimolecular systems (reactive or inelastic) involving ei-tion space; i.e., the Jacobian to be used in the differential ther diatomic molecules (3) or an atom and a small poly-element for the calculation of the Hamiltonian matrix eleatomic molecule (4), and (iii) the dynamical study of the ments is changed, so that the Hamiltonian operator must also relative degrees of freedom of dimers (5) or trimers (6) of be changed (1,10). small polyatomic molecules are the most difficult works that A general method for expressing with no approximation can be achieved.…”

Section: Introductionmentioning

confidence: 99%

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