Understanding molecular harmonic emission at relatively long intense laser pulses: Beyond the Born-Oppenheimer approximation

Abstract

The underlying physics behind the molecular harmonic emission in relatively long sin${}^2$-like laser pulses is investigated. We numerically solved the full-dimensional electronic time-dependent Schrödinger equation beyond the Born-Oppenheimer approximation for simple molecular ion H${}_2^{+}$. The occurrence and the effect of electron localization, non-adiabatic redshift and spatially asymmetric emission are evaluated to understand better complex patterns appearing in the high-order harmonic generation (HHG) spectrum. Results show that the complex patterns in the HHG spectrum originate mainly from a non-adiabatic response of the molecule to the rapidly changing laser field and also from a spatially asymmetric emission along the polarization direction. The effect of electron localization on the HHG spectrum was not observed as opposed to what is reported in the literature.

8 pages, 6 figures, Accepted to published in PRA

References in corpus (7)

• Molecular Orientation by Intense Single Cycle THz Pulses
• Time-frequency analysis of chaotic systems
• Detailed instantaneous ionization rate of H${}_2^{+}$ in intense laser field
• Effect of nuclear motion on high-order harmonic generation of H${}_2^{+}$ in intense ultrashort laser pulses
• Nuclear kinetic energy spectra of D_2^+ in intense laser field: Beyond Born Oppenheimer approximation
• Molecular alignment using circularly polarized laser pulses
• Complicated high-order harmonic generation due to the falling edge of a trapezoidal laser pulse

Cited by in corpus (3)

• Alignment dependent ultrafast electron-nuclear dynamics in high-order harmonic generation
• Full-dimensional treatment of short-time vibronic dynamics in molecular high-harmonics generation process in methane
• Contribution of the pre-ionized H${}_2$ and the ionized H${}_2^{+}$ subsystems to the HHG Spectra of H${}_2$ in intense laser fields