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Measuring The Angle-Dependent Photoionization Cross Section Of Nitrogen Using High-Harmonic Generation, Xiaoming Ren, Varun Makhija, Anh-Thu Le, Jan Troß, Sudipta Mondal, Cheng Jin, Vinod Kumarappan, Carlos A. Trallero-Herrero
Measuring The Angle-Dependent Photoionization Cross Section Of Nitrogen Using High-Harmonic Generation, Xiaoming Ren, Varun Makhija, Anh-Thu Le, Jan Troß, Sudipta Mondal, Cheng Jin, Vinod Kumarappan, Carlos A. Trallero-Herrero
Physics Faculty Research & Creative Works
We exploit the relationship between high harmonic generation (HHG) and the molecular photorecombination dipole to extract the molecular-frame differential photoionization cross section (PICS) in the extreme ultraviolet (XUV) for molecular nitrogen. A shape resonance and a Cooper-type minimum are reflected in the pump-probe time delay measurements of different harmonic orders, where high-order rotational revivals are observed in N₂. We observe the energy- and angle-dependent Cooper minimum and shape resonance directly in the laboratory-frame HHG yield by achieving a high degree of alignment, [SEE FORMULA IN ABSTRACT cos2 θ] 0.8. The interplay between PICS and rotational revivals is confirmed by simulations …
High Harmonic Spectroscopy Of The Cooper Minimum In Molecules, M. C. H. Wong, Anh-Thu Le, A. F. Alharbi, A. E. Boguslavskiy, R. R. Lucchese, J.-P. Brichta, C. D. Lin, V. R. Bhardwaj
High Harmonic Spectroscopy Of The Cooper Minimum In Molecules, M. C. H. Wong, Anh-Thu Le, A. F. Alharbi, A. E. Boguslavskiy, R. R. Lucchese, J.-P. Brichta, C. D. Lin, V. R. Bhardwaj
Physics Faculty Research & Creative Works
The Cooper minimum (CM) has been studied using high harmonic generation solely in atoms. Here, we present detailed experimental and theoretical studies on the CM in molecules probed by high harmonic generation using a range of near-infrared light pulses from λ = 1.3 to 1.8 µm. We demonstrate the CM to occur in CS₂ and CCl₄ at ~42 and ~40 eV, respectively, by comparing the high harmonic spectra with the known partial photoionization cross sections of different molecular orbitals, confirmed by theoretical calculations of harmonic spectra. We use CM to probe electron localization in Cl-containing molecules (CCl₄, CH₂Cl₂, and trans …