TWO-PHOTON EXCITATION, HYPER-RAMAN SCATTERING, AND EXCITED STATE DECAY PROCESSES FOR POLYENES IN FREE JET EXPANSIONS J.S. Horwitz, B.E. Kohler et T.A. Spiglanin J. Phys. Colloques, 46 C7 (1985) C7-381-C7-389 DOI: 10.1051/jphyscol:1985768