Abstract
The author presents a quantitative estimate of photon absorption cross sections due to forced dipole excitation in noble gas atoms by intense CO2 laser pulses. The cross sections for Xe, Kr, Ar and Ne are calculated using a dynamic model in which the electron cloud of a complex atom is treated as an inhomogeneous gas. The cross sections are used to obtain the saturation intensities in noble gas atoms at two CO2 laser frequencies, h(cross) omega =0.118 and 0.130 eV. A comparison with observed experimental saturation intensities, for an estimated effective interaction time of about 0.2 ps, shows remarkably close agreement between the predictions of the model and the data.