C[-X LASER EXCITATION SPECTRUM OF THE HG-AR VDW COMPLEX

We have measured the c(upsilon'=0-8)-X(upsilon=0) laser excitation spe ctrum of the Hg-Ar van der Waals complex. This corresponds to the firs t observation of the bound Hg-rare-gas complex in the dark c state. In this measurement, we employ the sequence of two laser pulses; the com plex is excited by the first one to the dark bound level in the c stat e and then successively excited by the second one to another bright st ate for the optical detection. The Birge-Sponer (BS) plot of the upsil on' progression is well fitted by a straight line, suggesting that the c-state potential curve of Hg-Ar is well approximated by the Morse fu nction. The linear fitting of this BS plot gives the potential paramet ers for the c state. (C) 1998 American Institute of Physics.