Orientation dependences of high-order harmonic generation in H2 and H2 + molecules

We propose a modified version for the strong field theory of high-order harmonic generation (HHG) in molecules and we apply it to analyze the orientation-dependences of HHG from the hydrogen molecule and it molecular ion H2+ when exposed to linearly polarized laser light. Our model predicts the presence of clear interference minima in the spectra of the high-order harmonics. We further exploit the orientation-dependence of the interference minima's position and the harmonics polarization properties through proposed model. We found that the position of the interference minima are associated with the polarization properties of harmonics.