Lifetime vibrational interference during the NO 1s-1π* resonant excitation studied by the NO+(A 1Π → X 1Σ+) fluorescence

A. Ehresmann; W. Kielich; L. Werner; Ph. V. Demekhin; D. V. Omel'yanenko; V. L. Sukhorukov; K.-H. Schartner; H. Schmoranzer

doi:10.1140/epjd/e2007-00274-6

2024 Impact factor 1.5

Atomic, Molecular, Optical and Plasma Physics

Eur. Phys. J. D 45, 235-246 (2007)
https://doi.org/10.1140/epjd/e2007-00274-6

Lifetime vibrational interference during the NO 1s^-1π^* resonant excitation studied by the NO⁺(A ¹Π → X ¹Σ⁺) fluorescence

A. Ehresmann¹, W. Kielich¹, L. Werner¹, Ph. V. Demekhin¹^,2, D. V. Omel'yanenko², V. L. Sukhorukov²^,3^a, K.-H. Schartner⁴ and H. Schmoranzer⁵

¹ Institute of Physics and CINSaT, University of Kassel, 34132 Kassel, Germany
² Rostov State University of Transport Communications, 344038 Rostov-on-Don, Russia
³ Institute of Physics, Southern Federal University, 344090 Rostov-on-Don, Russia
⁴ I. Institute of Physics, Justus-Liebig University Giessen, 35392 Giessen, Germany
⁵ Department of Physics, Kaiserslautern University of Technology, 67653 Kaiserslautern, Germany

Corresponding author: ^a vls@rgups.ru

Received: 17 April 2007
Revised: 6 July 2007
Published online: 26 September 2007

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 118–142 nm. This range is dominated by lines of atomic nitrogen and oxygen fragments and by the $A ~^{1}{\rm \Pi} \left(v^{\prime}\right) \rightarrow X ~^{1}{\rm \Sigma}^{+}\left(v^{\prime \prime}\right)$ 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 $X~^{2}{\rm \Pi}\left(v_{0}=0\right) \rightarrow$ N^*O $\left( {\rm NO}^{\ast}\right)$ $1s^{-1}\pi ^{\ast }\left( v_{r}\right)$ ⇒ NO $^{+}~A~^{1}{\rm \Pi} \left(v^{\prime}\right) \rightarrow X~^{1}{\rm \Sigma}^{+}\left(v^{\prime \prime}\right)$ were used to explain the observed intensity dependence for the $A\left(v^{\prime }\right) \rightarrow X\left(v^{\prime \prime}\right)$ 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 $A\left( v^{\prime}\right) \rightarrow X\left(v^{\prime \prime}\right)$ fluorescence intensity. A strong spin-orbit coupling between singlet and triplet states of NO⁺ is proposed to reduce additional cascade population of the $A~^{1}{\rm \Pi}$ state via radiative transitions from the $W~^{1}{\rm \Delta}$ and $A^{\prime}~^{1}{\rm \Sigma}^{-}$ states and to explain remaining differences between measured and calculated integral fluorescence intensities.

PACS: 32.80.Hd – Auger effect and inner-shell excitation or ionization / 33.80.-b – Photon interactions with molecules / 33.50.Dq – Fluorescence and phosphorescence spectra

© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007