Title: First-principles insights into ultrashort laser spectroscopy of molecular nitrogen,
Abstract: In this research, we employ accurate time-dependent density functional
calculations for ultrashort laser spectroscopy of nitrogen molecule. Laser
pulses with different frequencies, intensities, and durations are applied to
the molecule and the resulting photoelectron spectra are analyzed. It is argued
that relative orientation of the molecule in the laser pulse significantly
influence the orbital character of the emitted photoelectrons. Moreover, the
duration of the laser pulse is also found to be very effective in controlling
the orbital resolution and intensity of photoelectrons. Angular resolved
distribution of photoelectrons are computed at different pulse frequencies and
recording times. By exponential growth of the laser pulse intensity, the
theoretical threshold of two photons absorption in nitrogen molecule is
determined.