Alignment dependence of photoelectron momentum distributions for diatomic molecules N$_2$ in strong elliptical laser fields

Abstract

We study ionization dynamics of aligned diatomic molecules N2 in strong elliptical laser fields experimentally and theoretically. The alignment dependence of photoelectron momentum distributions (PMDs) of N2 measured in experiments is highlighted with comparing to Ar measured synchronously. Our results show that the PMDs of N2 depend strongly on the alignment of the molecule, relative to the main axis of the laser ellipse. In particular, the most-probable electronemission angle which is often used in attosecond measurement, differs remarkably when changing the molecular alignment. We show that the interplay of two-center interference and tunneling when the electron goes through the laser-Coulomb-formed barrier, plays an important role in these phenomena. Our work gives suggestions on studying ultrafast electron motion inside aligned molecules.