Nonadiabatic electron dynamics effects on high-harmonic generation spectrum of [formula omitted]: Minima and oscillatory pattern

Abstract

We numerically solved the full-dimensional electronic time-dependent Schrödinger equation for H2+ with Born-Oppenheimer approximation under different sin2-shaped and trapezoidal laser pulses at some different wavelengths, with I = 1 × 1013, 3 × 1013 and 6 × 1013 Wcm−2 intensity at 4.73 a.u. and 7.0 a.u. internuclear distances. Some structures such as minima and oscillatory patterns appearing in the high-order harmonic generation (HHG) spectra. We evaluate these structures in the HHG spectrum by considering the electron localization, electron nonadiabatic dynamics, and the Rabi oscillation of the population of the ground and excited electronic states. We have explored that these minima originate from the oscillatory patterns and different phase in the Sgω and Suω spectra due to recombination to the 1σg and 2pσu respectively. These oscillatory patterns in turn are due to the nonadiabatic electronic behavior appearing as a slow oscillation pattern in the ground and first excited electronic states populations. We show that the minima of the HHG spectrum are related to Sgω, Suω, and orbital interference.