Absolute Measurement of the Photoionization Cross Section of the Excited 7p State of Potassium

The absolute photoionization cross section for the excited 7p state of K has been measured using the method of ionization saturation. The measured cross sections σ_7p (321.8nm) and σ_7p (643.6nm) are (0.9±0.6) Mb and (1.9±0.9)Mb, respectively. The results are in good agreement with the calculated values.