One and two-center processes in high-order harmonic generation in diatomic molecules: influence of the internuclear separation

Abstract

We analyze the influence of different recombination scenarios, involving one or two centers, on high-order harmonic generation (HHG) in diatomic molecules, for different values of the internuclear separation. We work within the strong-field approximation, and employ modified saddle-point equations, in which the structure of the molecule is incorporated. We find that the two-center interference patterns, attributed to high-order harmonic emission at spatially separated centers, are formed by the quantum interference of the orbits starting at a center $C_j$ and finishing at a different center $C_{\nu }$ in the molecule with those starting and ending at a same center $C_j.$ Within our framework, we also show that contributions starting at different centers exhibit different orders of magnitude, due to the influence of additional potential-energy shifts. This holds even for small internuclear distances. Similar results can also be obtained by considering single-atom saddle-point equations and an adequate choice of molecular prefactors.

8 pages, 5 figures

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Cited by in corpus (1)

• Extracting an electron's angle of return from shifted interference patterns in macroscopic high-harmonic spectra of diatomic molecules