TY - JOUR
T1 - Autoionization dynamics and Feshbach resonances
T2 - Femtosecond EUV study of O2 excitation and dissociation
AU - Gagnon, Etienne
AU - Sharma, Vandana
AU - Li, Wen
AU - Santra, Robin
AU - Ho, Phay
AU - Ranitovic, Predrag
AU - Cocke, C. L.
AU - Murnane, Margaret M.
AU - Kapteyn, Henry C.
AU - Sandhu, Arvinder S.
N1 - Funding Information:
We thankfully acknowledge support from the NSF and U.S. Department of Energy.
Funding Information:
In this work, we use a reaction microscope in conjunction with a tabletop ultrafast EUV light source to study the behavior of molecular oxygen when illuminated by 42.7 eV photons. We use this novel approach to perform a direct time-resolved observation of a highly excited molecular system. Using EUV pump-IR probe, we observe the birth of a Feshbach resonance in the neutral oxygen atom with a negative binding energy. We monitor, in real-time, the autoionization dynamics that occurs in highly excited O2 and find that the lower limit for autoionization timescale is ~300fs. We thankfully acknowledge support from the NSF and U.S. Department of Energy.
PY - 2009
Y1 - 2009
N2 - In this work, we present a time-domain study of the complex, multi-step, evolution of highly excited states of oxygen (O2) that result from EUV photoionization. By monitoring the dissociation of molecular oxygen ions, we show that autoionization cannot occur until the internuclear separation is 30 or greater. As the ion and excited neutral atom separate, we directly observe the transformation of electronically bound states of the molecular ion into Feshbach resonances of the neutral oxygen atom. We achieve this by using laser high-harmonics in a femtosecond EUV-IR pump-probe scheme, combined with a triple coincidence reaction microscope measurement. Finally, we show control of the dissociation pathway through IR pulse induced ionization.
AB - In this work, we present a time-domain study of the complex, multi-step, evolution of highly excited states of oxygen (O2) that result from EUV photoionization. By monitoring the dissociation of molecular oxygen ions, we show that autoionization cannot occur until the internuclear separation is 30 or greater. As the ion and excited neutral atom separate, we directly observe the transformation of electronically bound states of the molecular ion into Feshbach resonances of the neutral oxygen atom. We achieve this by using laser high-harmonics in a femtosecond EUV-IR pump-probe scheme, combined with a triple coincidence reaction microscope measurement. Finally, we show control of the dissociation pathway through IR pulse induced ionization.
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U2 - 10.1088/1742-6596/194/1/012014
DO - 10.1088/1742-6596/194/1/012014
M3 - Article
AN - SCOPUS:74049094750
SN - 1742-6588
VL - 194
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
M1 - 012014
ER -