Vibrational wavepacket motion in I-2 excited with femtosecond laser pulsesin the 200 nm wavelength region

Using 130 fs laser pulses with a photon energy of about 6.2 eV, vibrational wavepackets in high-lying electronic states of the iodine molecule are exc ited and observed by the pump-probe technique. The coherent vibrational mot ion with a frequency of about 60 cm(-1) first experiences a collapse. Furth ermore, two distinct revivals are observed attributed to the vibrational mo tion on the D(0(u)(+)) and, most probably, on the beta(1(g)) ion-pair poten tial energy curves. The different behaviour of jet-cooled and warm molecule s is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.