Control and identification of strong field dissociative channels in ... via molecular alignment

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2014-06, Vol.47 (12), p.1-11
• Main Authors: Oppermann, M, Weber, S J, Morales, F, Richter, M, Patchkovskii, S, Csehi, A, Vibok, A, Ivanov, M, Smirnova, O, Marangos, J P
• Format: Article
• Language: English
• Subjects: Alignment; Channels; Excitation; Ionization; Lasers; Polarization; Simulation; Texts
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/0953-4075/47/12/124025

The dissociative excitation of (ProQuest: Formulae and/or non-USASCII text omitted) was studied in the molecular frame as a function of probe laser intensity, ellipticity and polarization with respect to the molecular bond at laser wavelengths of 800 nm and 1350 nm. This allowed the identification of the main excitation pathway consisting of tunnel ionization from HOMO-2 followed by a parallel dipole transition from the second excited state B to the predissociating, third excited state C. Recollision excitation was shown to play a negligible role. Using laser induced impulsive alignment, the strong field induced coupling at 800 nm and 1350 nm of the ionic states B and C could thus be controlled by the laser polarization. This leads to a suppression of the fragmentation yield of up to 70% when the laser polarization was perpendicular to the molecular axis compared to parallel polarization. We have performed simulations of various ionization channels of CO sub(2). Our simulations reflect the experimental findings and show that dissociation of (ProQuest: Formulae and/or non-USASCII text omitted) is induced by tunnelling from deeper molecular orbitals HOMO-1, HOMO-2, HOMO-3, followed by laser driven hole dynamics in the ion.