Three-dimensional tomographic imaging of CO molecular orbitals reveals multi-electron effects

Abstract

According to the asymmetric molecular orbital reconstruction algorithm, which divides orbital into gerade and ungerade components and which does not depend on the unidirectional recollisional condition, we obtain the two-dimensional highest occupied molecular orbital (HOMO) of CO based on the directly calculated transition dipole moment and the harmonic spectra calculated by the Lewenstein model, respectively, which is the three-dimensional (3D) HOMO projected onto the plane perpendicular to the laser propagation direction. In order to retrieve the full orbital function, a 3D molecular orbital tomography (MOT) method is developed and is successfully applied to the reconstructions of the HOMO of CO, which simplifies the 3D imaging process of orbitals of linear molecules, and is expected to be extended to reconstruct the 3D orbitals of nonlinear molecules. In addition, the time-dependent density functional theory is employed to acquire the harmonic spectra of CO in a 800 nm and 1500 nm wavelength laser, respectively. The comparison of these two reconstruction results helps identify the multi-electron effects for asymmetric MOT, which requires further study. This work advances the development of MOT and is expected to reveal multi-electron effects in orbital imaging of complex polyatomic molecules.

Elliptically polarized high-order harmonic generation in nitrogen molecules with cross-linearly polarized two-color laser fields

“…[3][4][5][6][7][8] In addition, high-order harmonics contain rich information of the atomic and molecular targets, providing a unique way of probing the structure and dynamics of targets. [9][10][11] In particular, circularly or elliptically polarized high-order harmonics have greater value in numerous applications, such as chiral recognition studies, [12] ultrafast chiral-specific dynamics in molecules, [13] and magnetic circular dichroism spectroscopy. [14,15] According to the semiclassical three-step model, the electron recombines with the parent core along the laser polarization direction when driven by linearly polarized laser fields.…”