Journal article
Lifetime vibrational interference during the NO 1s⁻¹π* resonant excitation studied by the NO⁺(A ¹Π → X ¹Σ⁺) fluorescence
Publication Details
Authors: | Ehresmann, A.; Kielich, W.; Werner, L.; Demekhin, P.; Omel'yanenko, D.; Sukhorukov, V.; Schartner, K.; Schmoranzer, H. |
Publication year: | 2007 |
Journal: | The European Physical Journal D |
Pages range : | 235-246 |
Volume number: | 45 |
ISSN: | 1434-6060 |
eISSN: | 1434-6079 |
DOI-Link der Erstveröffentlichung: |
URN / URL: |
Abstract
Dispersed fluorescence from fragments formed after the de-excitation of the 1s-1π* resonances of N*O and NO* has been measured in the spectral range of 118-142nm. This range is dominated by lines of atomic nitrogen and oxygen fragments and by the A1Π(v′) → X1Σ+(v′′) bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances. Ab-initio calculations of the transition probabilities between vibrational levels during the reaction NO X2Π(v0=0)→ N*O (NO*) 1s-1π*(vr) ⇒ NO+ A1Π(v′) → X1Σ+(v′′) were used to explain the observed intensity dependence for the A(v′) → X(v′′) fluorescence bands on the exciting-photon energy across the resonances and on both v′ and v′′ vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the A(v′) → X(v′′) fluorescence intensity. A strong spin-orbit coupling between singlet and triplet states of NO+ is proposed to reduce additional cascade population of the A1Π state via radiative transitions from the W1Δ and A′1Σ- states and to explain remaining differences between measured and calculated integral fluorescence intensities.
Dispersed fluorescence from fragments formed after the de-excitation of the 1s-1π* resonances of N*O and NO* has been measured in the spectral range of 118-142nm. This range is dominated by lines of atomic nitrogen and oxygen fragments and by the A1Π(v′) → X1Σ+(v′′) bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances. Ab-initio calculations of the transition probabilities between vibrational levels during the reaction NO X2Π(v0=0)→ N*O (NO*) 1s-1π*(vr) ⇒ NO+ A1Π(v′) → X1Σ+(v′′) were used to explain the observed intensity dependence for the A(v′) → X(v′′) fluorescence bands on the exciting-photon energy across the resonances and on both v′ and v′′ vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the A(v′) → X(v′′) fluorescence intensity. A strong spin-orbit coupling between singlet and triplet states of NO+ is proposed to reduce additional cascade population of the A1Π state via radiative transitions from the W1Δ and A′1Σ- states and to explain remaining differences between measured and calculated integral fluorescence intensities.
