Reactivity and electronic states of O4 along minimum energy paths

Hernández‐Lamoneda, Ramón; Ramı́rez-Solı́s, A.

doi:10.1063/1.1288370

Cited by 51 publications

(48 citation statements)

References 41 publications

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“…At the same time, the calculations of the O( 3 P) + O 3 PES performed at the CAS(16,12) + CASMP2/ANO-TZ level did not show any remarkable minimum corresponding to this complex 16 It should also be noted that a similar situation takes place for the existence of the complex O 2 ···O at the PES calculated at very comprehensive levels of theory. 122,123 The comparison of the kinetic constants was calculated using very accurate PESs (which have a local minimum corresponding to the O 2 ···O complex) does imperfectly agree with the available experimental data, whereas the artificial removal of the local minimum from the PES gives perfect agreement with experimental values.…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 62%

“…It was supposed earlier on the basis of CAS(6,6), CAS (8,8), and CAS (16,12) calculations 20 that the O 4 system could be described correctly in the CAS(24,16) active space. To our knowledge, such a kind of theory has not been applied to O 4 molecules up to date because it is considered impractical.…”

Section: Resultsmentioning

confidence: 95%

“…This is justified by calculations with reduced selection criteria (T pre and T sel ) to 10 −7 and 10 −9 au (the resulting E r value is changed by 1.6 kJ mol −1 ). This is likely aroused from an imbalanced treatment of electron correlation by simplified MR-DDCI-3 wave functions in the truncated model CAS (16,12) active space with respect to MRCI+Q. Hence, we conclude that the MRCI+Q/cc-pVTZ theory level provides a reliable estimate for the E r in both active spaces, whereas the MR-DDCI-3 method is valid only in the largest active space CAS (24,16).…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 84%

“…Active space CAS (16,14) for O 6 does not converge correctly to dissociation limit O 6 → 2O 3 . We suppose that the full valence active space CAS(24,18) is enough to describe the reaction path because it includes all (quasi)degenerate orbitals, and active space CAS (12,9) shows correct results for the ozone molecule.…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 95%

“…However, in the present study, we found the correct active space to describe both O 4 molecules. Thus, it made it possible to carry out the energy refinements using MRCI methods in the CAS (24,16) Energies of some hypothetical reactions of the O 4 isomers' production calculated at the CCSD(T)/cc-pCVTZ and CCSDT(Q)/cc-pVTZ (in parentheses) levels and using MRCI+Q/cc-pVTZ//CCSD(T)/cc-pCVTZ and MRCI-DDCI-3/cc-pVTZ//CCSD(T)/cc-pCVTZ composite approaches (in brackets) are Both O 4 isomers are much higher in energy than molecular oxygen in both the triplet and singlet states. The quasi-isolated…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 99%

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Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

Gadzhiev

Ignatov

Куликов

et al. 2012

J. Chem. Theory Comput.

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Recent experiments on the UV and electron beam irradiation of solid O 2 reveals a series of IR features near the valence antisymmetric vibration band of O 3 which are frequently interpreted as the formation of unusual O n allotropes in the forms of weak complexes or covalently bound molecules. In order to elucidate the question of the nature of the irradiation products, the structure, relative energies, and vibrational frequencies of various forms of O n (n = 1−6) in the singlet, triplet, and, in some cases, quintet states were studied using the CCSD(T) method up to the CCSD(T,full)/cc-pCVTZ and CCSD(T,FC)/aug-cc-pVTZ levels. The results of calculations demonstrate the existence of stable highly symmetric structures O 4 (D 3h ), O 4 (D 2d ), and O 6 (D 3d ) as well as the intermolecular complexes O 2 ·O 2 , O 2 ·O 3 , and O 3 ·O 3 in different conformations. The calculations show that the local minimum corresponding to the O 3 ···O complex is quite shallow and cannot explain the ν 3 band features close to 1040 cm −1 , as was proposed previously. For the ozone dimer, a new conformer was found which is more stable than the structure known to date. The effect of the ozone dimer on the registered IR spectra is discussed.

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Section: Journal Of Chemical Theory and Computationmentioning

confidence: 62%

Section: Resultsmentioning

confidence: 95%

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 84%

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 95%

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 99%

See 3 more Smart Citations

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

Gadzhiev

Ignatov

Куликов

et al. 2012

J. Chem. Theory Comput.

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On the “Ozone Deficit Problem”: What Are Ox and HOx Catalytic Cycles for Ozone Depletion Hiding?

Varandas

2002

ChemPhysChem

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Studies on the role of vibrational excitation in the reactants for the O2+O2, OH+O2, and HO2+O2 reactions show that they can be important sources of ozone in the stratosphere, particularly at conditions of local thermodynamic disequilibrium. The results suggest that the Ox and HOx cycles commonly viewed as catalytic sinks of ozone may actually lead to its production, and hence help to clarify the “ozone deficit problem”. This paper also presents an explanation for the general overestimation of the OH abundance in the upper stratosphere and lower mesosphere through standard HOx chemistry.

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Experimental Detection of Tetraoxygen

2001

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The search for tetraoxygen, which dates back to a study by Lewis in 1924, [1] is being actively pursued, owing to its fundamental interest, its potential role as a material of high energy density, [2] and, in particular, the current upsurge of interest in excited states of O 2 with relevance to atmospheric chemistry and to terrestrial and Venusian nightglow. [3] Numerous calculations at different levels of theory predict the existence of metastable O 4 molecules with a D 2d cyclic geometry [4] or a D 3h ªpinwheelº geometry. [5,6] Positive experimental detection of such species has not been reported, whereas weakly bonded (O 2 ) 2 van der Waals dimers, with dissociation enthalpies of less than 1 kcal mol À1 , have long been known and thoroughly characterized. [7] Indirect evidence for metastable tetraoxygen was derived from experiments involving electron transfer from Cs to O 4 , followed by the measurement of the kinetic energy spectrum of the O 2 fragments. The structure of the kinetic energy distribution was consistent with the intervention of some O 4 species that were not observable under the conditions of the experiment. [8] Strong evidence for metastable O 4 was derived from studies involving the photoionization of O 2 excited by a DC discharge. [9,10] Interestingly, the results of both experimental studies were interpreted as suggestive of the existence of a third metastable O 4 species in addition to the theoretically predicted molecules, namely, a relatively long lived complex between a ground-state O 2 molecule and an O 2 molecule in the excited c 1 S À u electronic state. [10] To obtain conclusive proof, we have carried out an experiment aimed at detecting intact O 4 . Our approach is also based, like previous studies, [8] on the neutralization of O 4 cations in the gas phase, but uses for the identification of the intact O 4 molecule neutralization reionization (NR) mass spectrometry [11] on a highly sensitive instrument that allowed the detection of other elusive atmospheric species, such as hydrogen trioxide [12] and the [H 2 O ´O 2 À ] charge-transfer complex. [13] The O 4 ions were generated in a chemical ionization (CI) source by association of O 2 molecules with O 2 primary ions, formed both in the X 2 P g ground state and in electronically excited states by electron impact. [14] The ions were then accelerated through 4 ± 8 keV, magnetically mass resolved, and probed by collisionally activated dissociation (CAD) mass spectrometry. Whereas the CAD spectrum of 16 O 4 from the ionization of 16 O 2 shows 16 O 2 as the charged fragment, 16 O 2 18 O 2 ions from 16 O 2 / 18 O 2 mixtures give 16 O 2 and 18 O 2 without the 16 O 18 O ions [15] that would suggest isotopic scrambling ( Figure 1). This shows that the O 4 ions probed contain two discrete O 2 units, each of which retains its original identity.In the NR experiments the O 4 ions were also accelerated to 4 ± 8 keV and mass-selected before undergoing two consecutive collision events in separate cells aligned along the beam path. In the first c...

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Reactivity and electronic states of O4 along minimum energy paths

Abstract: Articles you may be interested inRadiative lifetimes of spin forbidden a 1Δ → X 3Σ− and spin allowed A 3Π → X 3Σ− transitions and complete basis set extrapolated ab initio potential energy curves for the ground and excited states of CH−

Cited by 51 publications

References 41 publications

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

On the “Ozone Deficit Problem”: What Are Ox and HOx Catalytic Cycles for Ozone Depletion Hiding?

Experimental Detection of Tetraoxygen

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Reactivity and electronic states of O4 along minimum energy paths

Abstract: Articles you may be interested inRadiative lifetimes of spin forbidden a 1Δ → X 3Σ− and spin allowed A 3Π → X 3Σ− transitions and complete basis set extrapolated ab initio potential energy curves for the ground and excited states of CH−

Cited by 51 publications

References 41 publications

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes On (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes On (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

On the “Ozone Deficit Problem”: What Are Ox and HOx Catalytic Cycles for Ozone Depletion Hiding?

Experimental Detection of Tetraoxygen

Contact Info

Product

Resources

About

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level

Structure, Energy, and Vibrational Frequencies of Oxygen Allotropes O_n (n ≤ 6) in the Covalently Bound and van der Waals Forms: Ab Initio Study at the CCSD(T) Level