Large impact of the weak direct photoionization on the angularly resolved CO+(A2) de-excitation spectra of the CO*(112) resonance

Ph V Demekhin (1) , I D Petrov (2) , T Tanaka (3) , M Hoshino (3) , H Tanaka , K Ueda (3, 4) , W Kielich (1) , A Ehresmann (1)

1 Institute of Physics and CINSaT
2 Rostov State University of Transport Communications
3 Department of Physics
4 Institute of Multidisciplinary Research for Advanced Materials

of the weak direct photoionization on angularly resolved CO + (A 2 Π) de-excitation spectra of the CO * (1σ −1 2π) resonance Abstract. Interference between the direct and resonant amplitudes for the population of the CO + (A 2 Π) state in the vicinity of the O 1s → 2π excitation of CO * is studied by an ab initio theoretical approach. The weak direct photoionization induces Fano-Shore type profiles resulting in long-range exciting-photon energy dependencies of the computed angular distribution parameters for the CO + (A 2 Π) photoelectrons, β e A (ω), and for the subsequent CO + A 2 Π → X 2 Σ + fluorescence, β2 X A (ω). In the presence of the direct photoionization, the lifetime vibrational interference causes substantial variations of the computed parameter β e A (ω) across the positions of the CO * (v r) vibronic states. Theoretical results are in qualitative agreement with the vibrationally and angularly resolved CO + (A 2 Π) resonant Auger electron spectra recorded in the Raman regime at different exciting-photon energies across the CO * resonance.

Mots clés: 33.80.-b; 32.80.Hd; 33.50.Dq

Ph V Demekhin, I D Petrov, T Tanaka, M Hoshino, H Tanaka, et al.. Large impact of the weak direct photoionization on the angularly resolved CO+(A2) de-excitation spectra of the CO*(112) resonance. Journal of Physics B: Atomic, Molecular and Optical Physics, 2010, 43 (6), pp.65102. ⟨10.1088/0953-4075/43/6/065102⟩. ⟨hal-00569879⟩