Potential Energy Curves for the 1Σ+ and 1,3Π States of CO

Vázquez, Gerardo J.; Amero, J. M.; Liebermann, Heinz‐Peter; Lefebvre‐Brion, H.

doi:10.1021/jp902730d

Cited by 39 publications

(34 citation statements)

References 55 publications

(102 reference statements)

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“…27 This discrepancy arises from the large electronic interactions mixing the W state with remote levels of the E 1 state and other Rydberg 1 states, whose perturbing effect is isotopologue dependent. 2 An estimate of the equilibrium internuclear separation, R e , of the perturber state may be made from its equilibrium rotational constant, B e , according to 39…”

Section: Deperturbation Of Energy Levelsmentioning

confidence: 99%

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Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

Heays

Eidelsberg

Stark

et al. 2014

The Journal of Chemical Physics

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We observe photoabsorption of the W(1) ← X(0) band in five carbon monoxide isotopologues with a vacuum-ultraviolet Fourier-transform spectrometer and a synchrotron radiation source. We deduce transition energies, integrated cross sections, and natural linewidths of the observed rotational transitions and find a perturbation affecting these. Following a deperturbation analysis of all five isotopologues, the perturbing state is assigned to the v = 0 level of a previously unobserved (1)Π state predicted by ab initio calculations to occur with the correct symmetry and equilibrium internuclear distance. We label this new state E″ (1)Π. Both of the interacting levels W(1) and E″(0) are predissociated, leading to dramatic interference effects in their corresponding linewidths.

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Section: Deperturbation Of Energy Levelsmentioning

confidence: 99%

“…26 Vázquez et al 27 further included molecular orbitals representing Rydberg states in a calculation of 1 + and 1, 3 states. Some of the experimentally important …”

Section: Introductionmentioning

confidence: 99%

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

Heays

Eidelsberg

Stark

et al. 2014

The Journal of Chemical Physics

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“…Essentially the same comments apply to the UV excited states of the isoelectronic molecule CO. Ref. 39 provides a recent example. In this paper we perform calculations for the N 2 molecules because of the availability of the relevant potential energy curves at sufficient levels of precision.…”

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confidence: 99%

On the strong and selective isotope effect in the UV excitation of N ₂ with implications toward the nebula and Martian atmosphere

Muskatel

Remacle

Thiemens

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Isotopic effects associated with molecular absorption are discussed with reference to natural phenomena including early solar system processes, Titan and terrestrial atmospheric chemistry, and Martian atmospheric evolution. Quantification of the physicochemical aspects of the excitation and dissociation processes may lead to enhanced understanding of these environments. Here we examine a physical basis for an additional isotope effect during photolysis of molecular nitrogen due to the coupling of valence and Rydberg excited states. The origin of this isotope effect is shown to be the coupling of diabatic electronic states of different bonding nature that occurs after the excitation of these states. This coupling is characteristic of energy regimes where two or more excited states are nearly crossing or osculating. A signature of the resultant isotope effect is a window of rapid variation in the otherwise smooth distribution of oscillator strengths vs. frequency. The reference for the discussion is the numerical solution of the time dependent Schrödinger equation for both the electronic and nuclear modes with the light field included as part of the Hamiltonian. Pumping is to all extreme UV dipole-allowed, valence and Rydberg, excited states of N 2 . The computed absorption spectra are convoluted with the solar spectrum to demonstrate the importance of including this isotope effect in planetary, interstellar molecular cloud, and nebular photochemical models. It is suggested that accidental resonance with strong discrete lines in the solar spectrum such as the CIII line at 97.703 nm can also have a marked effect.photodissociation | isotopic fractionation | UV photodissociation P hotochemical processes are particularly pervasive in nature. Measurements of isotopic compositions provide insights into a range of such processes, both terrestrial and extraterrestrial. To adequately interpret such measurements, characterization of relevant isotopically selective physicochemical processes associated with gas phase processes is desirable. In this paper we quantify an isotopic selectivity due to electronic reorganization following ligfht absorption. The results are compared to the solar spectrum for applications in nature.There are a number of photodissociation processes that have been suggested where a more basic understanding of isotope effects could aid in the development of models. A striking example of observed, but presently not fully understood oxygen isotopic distribution occurs in the high temperature calcium aluminum rich inclusions of the Allende meteorite (1) and most oxygen bearing meteorites (see, for example, review in ref.2). Although originally thought to be nucleosynthetic in origin based upon laboratory experiments, it was later suggested that the observed isotopic composition might arise from photochemical self-shielding (3-6). It has also been proposed that given the special properties of oxygen, symmetry related properties might produce the same fraction in the actual mineral formation process (7-11). A...

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“…It is likely that such resonances are associated with parent target states that is not well-represented in our model. The higher-lying electronic states in CO are increasingly Rydberg-like [43,87] and therefore difficult to represent using standard target models. Furthermore, including such Rydberg states in a scattering calculation remains very challenging [47] and will probably require further work on the methodology we use for such scattering calculations, for example the routine use of extended R-matrix spheres.…”

Section: Resultsmentioning

confidence: 99%

Higher lying resonances in low-energy electron scattering with carbon monoxide*

Dora

Tennyson

Chakrabarti³

2016

Eur. Phys. J. D

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Abstract. R-matrix calculations on electron collisions with CO are reported whose aim is to identify any higher-lying resonances above the well-reported and lowest 2 Π resonance at about 1.6 eV. Extensive tests with respect to basis sets, target models and scattering models are performed. The final results are reported for the larger cc-pVTZ basis set using a 50 state close-coupling (CC) calculation. The BreitWigner eigenphase sum and the time-delay methods are used to detect and fit any resonances. Both these methods find a very narrow 2 Σ + symmetry Feshbach-type resonance very close to the target excitation threshold of the b 3 Σ + state which lies at 12.9 eV in the calculations. This resonance is seen in the CC calculation using cc-pVTZ basis set while a CC calculation using the cc-pVDZ basis set does not produce this feature. The electronic structure of CO − is analysed in the asymptotic region; 45 molecular states are found to correlate with states dissociating to an anion and an atom. Electronic structure calculations are used to study the behaviour of these states at large internuclear separation. Quantitative results for the total, elastic and electronic excitation cross sections are also presented. The significance of these results for models of the observed dissociative electron attachment of CO in the 10 eV region is discussed.

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Potential Energy Curves for the ¹Σ⁺ and ^1,3Π States of CO

Cited by 39 publications

References 55 publications

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

On the strong and selective isotope effect in the UV excitation of N ₂ with implications toward the nebula and Martian atmosphere

Higher lying resonances in low-energy electron scattering with carbon monoxide*

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Potential Energy Curves for the 1Σ+ and 1,3Π States of CO

Cited by 39 publications

References 55 publications

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)

On the strong and selective isotope effect in the UV excitation of N 2 with implications toward the nebula and Martian atmosphere

Higher lying resonances in low-energy electron scattering with carbon monoxide*

Contact Info

Product

Resources

About

Potential Energy Curves for the ¹Σ⁺ and ^1,3Π States of CO

On the strong and selective isotope effect in the UV excitation of N ₂ with implications toward the nebula and Martian atmosphere