Computation of high-harmonic generation spectra of the hydrogen molecule using time-dependent configuration-interaction

ABSTRACT

Here we apply and expand the knowledge developed in the case of the H atom to describe high-harmonic generation (HHG) for the H₂ molecule by using time-dependent configuration interaction with single excitations. The implications of using a finite atomic orbital basis set and the impact of a heuristic lifetime model which addresses ionisation losses are discussed. We also examine the influence of the angular momentum of the basis on the computed HHG spectra. Moreover, we discuss the impact of adding diffuse functions and ghost atoms in different geometrical configurations around the molecule. The effects of these additional centres on the HHG spectra are correlated with the physical interpretation of this nonlinear optical phenomenon as given by the three-step model, relating the maximal radial extent of the electron as predicted by the model to the radial extent of the Gaussian basis sets.

GRAPHICAL ABSTRACT

KEYWORDS:

• High-harmonic generation
• strong field
• time-dependent configuration interaction

Acknowledgements

The authors gratefully acknowledge the advice of Tillmann Klamroth, Boyke Schönborn, V. Véniard, and C. William McCurdy.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

France Berkeley Fund [Grant Number FBF 2014-0020]; Office of Science, Office of Basic Energy Sciences, the US Department of Energy: Contract No. DE-AC02- 05CH11231.