Role of molecular alignment in attosecond photoionization of N2

We theoretically study the influence of molecular alignment on the attosecond photoionization of the ${\mathrm{N}}_{2}$ molecule. Based on the numerical simulations of the single-active-electron two-dimensional time-dependent Schr\"odinger equation, we find that the alignment-averaged photoelectron momentum distributions deviate from the single-molecule result, especially for a large molecular alignment angle and a low degree of molecular alignment. As a result, the photoemission time delays extracted from the angular-averaged streaking spectra are different from the single-molecule result. More importantly, the alignment-averaged photoemission time delays are found to depend on the degree of molecular alignment as well as the molecular alignment distribution. Our results reveal the important role of molecular alignment in the molecular attosecond photoionization.