Selective generation and control of excited vibrational wave packets in the electronic ground state of K-2

We investigate the generation and real-time monitoring of coherent vibratio nal wave packets in the electronic ground state of supersonic jet-cooled po tassium dimers. Vibrationally excited wave packets with mean quantum number s <(nu)over bar> = 6 and <(nu)over bar> = 11 are generated by a stimulated Raman process which is enhanced by an electronic resonance. Two ultrashort laser pulses of different wavelengths induce the pump and the dump process. The population of the final hot ground-state wave packets is successfully controlled by a variable time delay between the pump and the dump process, which enables us to wait with the dumping for the optimal Franck-Condon ove rlap between the intermediate and the predicted final vibrational wave pack et in the electronic ground state. (C) 1999 American Institute of Physics. [S0021-9606(99)00219-6].