Predissociation quantum yields of singlet nitrogen

Walter, C. W.; Cosby, P. C.; Helm, H.

doi:10.1103/physreva.50.2930

Cited by 41 publications

(43 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 The absorption is associated with dipole-allowed excitation of singlet ungerade ͑c n Ј 1 ⌺ u + , bЈ 1 ⌺ u + , c n 1 ⌸ u , o n 1 ⌸ u , and b 1 ⌸ u , where n is the principal quantum number͒ states, which are known to undergo strong predissociation, [2][3][4][5][6][7][8][9][10][11][12] some showing rotational dependence. 13 The rates of predissociation of these levels are key inputs in the radiation budget of the Earth's atmosphere, but the applicable predissociation mechanisms are far from being understood at present.…”

Section: Introductionmentioning

confidence: 99%

“…14 Lifetimes of the singlet ungerade states in N 2 have been measured using a wide variety of sophisticated experimental techniques. Laser-induced photofragment translational spectroscopy was performed in various studies 4,[6][7][8]10,12 that also provided direct information on the predissociation yields. Direct time domain studies have also been performed, either via the delayed coincidence technique combined with synchrotron radiation, 15 or via a vacuum ultraviolet-laser based pump-probe technique.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Sprengers

Ubachs

Baldwin

2005

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Sprengers

Ubachs

Baldwin

2005

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…1 All excited singlet states to which a dipole-allowed transition is possible from the electronic ground state lie above both the N( 4 S)ϩN( 4 S) and N( 4 S) ϩN( 2 D) dissociation limits. 2 One of the mechanisms leading to dissociation is predissociation via excited states of ungerade symmetry upon electron impact; this process occurs in the aurorae. 3 Most of the excited states of u symmetry in the energy range 100 000-115 000 cm Ϫ1 undergo strong dissociation, with the notable exception of the c 4 Ј 1 ⌺ u ϩ , v ϭ0 Rydberg state and the b 1 ⌸ u , vϭ1 valence state, which are known to produce intense extreme ultraviolet ͑XUV͒ and near UV emissions.…”

Section: Introductionmentioning

confidence: 99%

Predissociation in b 1Πu,v (v=1,4,5,6) levels of N2

Ubachs

Velchev

Lange

2000

The Journal of Chemical Physics

View full text Add to dashboard Cite

In a high-resolution laser spectroscopic study, using a tunable Fourier-transform limited light source in the extreme ultraviolet, the b 1 ⌸ u excited valence state of molecular nitrogen is reinvestigated for vibrational levels vϭ1, 4, 5, and 6. From line broadening of individual rotational levels excited state lifetimes were determined: (vϭ1) ϭ1.1Ϯ0.3 ns, (vϭ4) ϭ18Ϯ1 ps, (vϭ5) ϭ205Ϯ25 ps, and (vϭ6) ϭ350Ϯ75 ps. Additionally, the lifetime of the o 3 1 ⌸ u , vϭ0 Rydberg state was determined: ϭ240Ϯ50 ps. For the b 1 ⌸ u , vϭ1 state improved rotational constants were determined.

show abstract

“…The predissociation lifetimes are comparatively short compared to the lifetime for spontaneous emission and/or collisional deactivation. Consequently, most excited molecules will dissociate (48,49) and the population is a reasonable approximation of the eventual isotope effect in dissociation.…”

mentioning

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.

View full text Add to dashboard Cite

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...

show abstract

Predissociation quantum yields of singlet nitrogen

Cited by 41 publications

References 17 publications

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Predissociation in b 1Πu,v (v=1,4,5,6) levels of N2

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

Contact Info

Product

Resources

About

Predissociation quantum yields of singlet nitrogen

Cited by 41 publications

References 17 publications

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Isotopic variation of experimental lifetimes for the lowest Πu1 states of N2

Predissociation in b 1Πu,v (v=1,4,5,6) levels of N2

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

Contact Info

Product

Resources

About

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