Temperature and mean axial momentum vs. laser intensity of electrons released from O$_2$ by an 800 nm ultrashort pulsed laser

A semi-empirical model is presented for the thermalized temperature $T$ and mean momentum in the direction of laser propagation <$p_{fz}$> of electrons released from O$_{2}$ after the passage of a focused $800$ nm ultrashort pulsed laser pulse vs. peak laser intensity $I_{0}$ to provide initial conditions for electrodynamic fluid simulations.

For this, theoretical kinetic energy spectra in different directions are modified with two adjustable parameters representing the effects of electron rescatter off its parent ion during the optical cycle subsequent to ionization.

The classical kinematics of rescatter, in conjunction with the spectral fits, is used to estimate <$p_{fz}$>.