Multiphoton ionization of inner-valence electrons and fragmentation of ethylene in an intense Ti : sapphire laser pulse

Using linearly polarized 200 fs Ti:sapphire laser pulses the multiphoton io nization and fragmentation of ethylene was studied. A model is proposed whi ch is able to satisfactorily predict the abundance of the different fragmen ts, C2H4+, C2H3+ and C2H2+ as a function of laser intensity. It is shown th at fragmentation of the molecule occurs as a result of multiphoton ionizati on of inner-valence electrons followed by radiationless transitions to vari ous dissociation channels of the molecular ion. (C) 1999 Elsevier Science B .V. All rights reserved.