Nuclear-Motion Effects in Attosecond Transient Absorption Spectroscopy of Molecules

Abstract

We investigate the characteristic effects of nuclear motion on attosecond transient absorption spectra in molecules by calculating the spectrum for different model systems. Two models of the hydrogen molecular ion are considered: one where the internuclear separation is fixed, and one where the nuclei are free to vibrate. The spectra for the fixed nuclei model are similar to atomic spectra reported elsewhere, while the spectra obtained in the model including nuclear motion are very different and dominated by extremely broad absorption features. These broad absorption features are analyzed and their relation to molecular dissociation investigated. The study of the hydrogen molecular ion validates an approach based on the Born-Oppenheimer approximation and a finite electronic basis. This latter approach is then used to study the three-dimensional hydrogen molecule including nuclear vibration. The spectrum obtained from H${}_2$ is compared to the result of a fixed-nuclei calculation. In the attosecond transient absorption spectra of H${}_2$ including nuclear motion we find a rich absorption structure corresponding to population of different vibrational states in the molecule, while the fixed-nuclei spectra again are very similar to atomic spectra. We find that light-induced structures at well-defined energies reported in atomic systems are also present in our fixed nuclei molecular spectra, but suppressed in the ${{\text{H}}_2}^{+}$ and H${}_2$ spectra with moving nuclei. We show that the signatures of light-induced structures are closely related to the nuclear dynamics of the system through the shapes and relative arrangement of the Born-Oppenheimer potential energy curves.

References in corpus (5)

• Transient absorption and reshaping of ultrafast XUV light by laser-dressed helium
• Theory of attosecond transient absorption spectroscopy of strong-field-generated ions
• Quantum interference in attosecond transient absorption of laser-dressed helium atoms
• Dissociation and dissociative ionization of H2+ using the time-dependent surface flux method
• Dissociative ionization of H2+ using intense femtosecond XUV laser pulses

Cited by in corpus (8)

• Probing autoionizing states of molecular oxygen with XUV transient absorption: Electronic symmetry dependent lineshapes and laser induced modification
• Light-Induced Structures in Attosecond Transient Absorption Spectroscopy of Molecules
• Analytic modeling of structures in attosecond transient-absorption spectra
• Attosecond transient-absorption spectroscopy of polar molecules
• Attosecond Transient Absorption Spectroscopy without Inversion Symmetry
• Many-body effects on high-harmonic generation in Hubbard ladders
• Simulating strong-field electron-hole dynamics in solids probed by attosecond transient absorption spectroscopy
• Nonadiabatic effects in attosecond transient absorption spectroscopy