Rotationally resolved absorption spectrum of the O2 dimer in the visible range

Campargue, A.; Biennier, Ludovic; Kachanov, Alexander A.; Jost, R.; Bussery‐Honvault, Béatrice; Veyret, Vincent; Churassy, S.; Bacis, R.

doi:10.1016/s0009-2614(98)00294-2

Cited by 47 publications

(41 citation statements)

References 27 publications

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“…The PESs were built combining ab initio calculations by Wormer and van der Avoird using first order exchange perturbation theory at the Hartree-Fock level 15 and a second-order polarization energy evaluated semiempirically, 16 circumventing in this way the difficulty inherent to an ab initio determination of the dispersion terms. Subsequent bound state calculations 17 were of great help in the analysis of the highly congested spectra recorded by Campargue et al and Biennier et al 18,19 Additional interesting information has come from scattering experiments by the Perugia group. 12,20 From these measurements, full dimensional PESs were obtained ͑hereafter referred as the Perugia PES͒.…”

Section: Introductionmentioning

confidence: 99%

Accurate ab initio intermolecular potential energy surface for the quintet state of the O2(Σg−3)–O2(Σg−3) dimer

Bartolomei

Carmona‐Novillo

Hernández

et al. 2008

The Journal of Chemical Physics

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A new potential energy surface ͑PES͒ for the quintet state of rigid O 2 ͑ 3 ⌺ g − ͒ +O 2 ͑ 3 ⌺ g − ͒ has been obtained using restricted coupled-cluster theory with singles, doubles, and perturbative triple excitations ͓RCCSD͑T͔͒. A large number of relative orientations of the monomers ͑65͒ and intermolecular distances ͑17͒ have been considered. A spherical harmonic expansion of the interaction potential has been built from the ab initio data. It involves 29 terms, as a consequence of the large anisotropy of the interaction. The spherically averaged term agrees quite well with the one obtained from analysis of total integral cross sections. The absolute minimum of the PES corresponds to the crossed ͑D 2d ͒ structure ͑X shape͒ with an intermolecular distance of 6.224 bohrs and a well depth of 16.27 meV. Interestingly, the PES presents another ͑local͒ minimum close in energy ͑15.66 meV͒ at 6.50 bohrs and within a planar skewed geometry ͑S shape͒. We find that the origin of this second structure is due to the orientational dependence of the spin-exchange interactions which break the spin degeneracy and leads to three distinct intermolecular PESs with singlet, triplet, and quintet multiplicities. The lowest vibrational bound states of the O 2 -O 2 dimer have been obtained and it is found that they reflect the above mentioned topological features of the PES: The first allowed bound state for the 16 O isotope has an X structure but the next state is just 0.12 meV higher in energy and exhibits an S shape.

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Section: Introductionmentioning

confidence: 99%

Accurate ab initio intermolecular potential energy surface for the quintet state of the O2(Σg−3)–O2(Σg−3) dimer

Bartolomei

Carmona‐Novillo

Hernández

et al. 2008

The Journal of Chemical Physics

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“…8 The collisional complexes relate to an O 2 -O 2 interaction potential, and the broad absorption features observed at room temperature correspond to continuum states at positive energies. In the negative energy region of the electronic ground state of the dimer, with a well depth of some 150 cm Ϫ1 due to van der Waals interactions, 9 there exist bound states that were investigated in a liquid-N 2 -cooled cell by Long and Ewing 10 and recently in jet experiments by Campargue et al 11 These ͑O 2 ͒ 2 van der Waals complexes should not be confused with covalently bound O 4 molecules that were observed in an electronically excited state. 12 An important result of previous work is that at room temperature no significant structure exists in the broad collisionally induced absorption bands; these features can be considered as essentially continuous even at the highest resolution.…”

Section: Introductionmentioning

confidence: 99%

Visible absorption bands of the (O_2)_2 collision complex at pressures below 760 Torr

Naus

Ubachs

1999

Appl. Opt.

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“…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.…”

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confidence: 97%

“…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.…”

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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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Rotationally resolved absorption spectrum of the O2 dimer in the visible range

Cited by 47 publications

References 27 publications

Accurate ab initio intermolecular potential energy surface for the quintet state of the O2(Σg−3)–O2(Σg−3) dimer

Accurate ab initio intermolecular potential energy surface for the quintet state of the O2(Σg−3)–O2(Σg−3) dimer

Visible absorption bands of the (O_2)_2 collision complex at pressures below 760 Torr

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

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