PHOTOEXCITATION OF POTASSIUM 3s WINDOW RESONANCES
M. Koide, F. Koike, M.-T. Huang, R. Welitz, B. DePaola,T. Nagata, S.
Ohtani, Y. Azuma, 
Institute for Laser Science, University of Electro-communications, Chofu,
Tokyo, Japan 
School of Medicine, Kitasato University, Sagamihara, Kanagawa, Japan
Photon Factory, Institute for Materials Structure Science, KEK, Ibaraki,
Tsukuba, Japan
Physics Department, Kansas State University, Manhattan, Kansas, U.S.A
Department of Science & Technology, Meisei University, Hino, Tokyo, Japan
     The photoion yield spectrum of K was measured over the 3s-np window
resonance region. Striking differences were found compared to the Ar 3s
window resonances. In K, the resonances are wide and  3s-4p excitation was
strongly enhanced whereas 3s-np (n≧5) were sharply suppressed. Results were
analyzed by performing MCDF calculation.