LASER SPECTROSCOPY OF SOME HGCD SPIN-ORBIT STATES

Fluorescence and excitation spectra arising from transitions between e xcited states of the HgCd exciplex molecule were produced in a mixture of Hg and Cd vapors following pump-and-probe laser excitation. The va por mixture, contained in a sealed quartz cell, was irradiated by puls ed pump (3261 Angstrom) and probe (4300-4750 Angstrom) laser beams, de layed by 450 ns relative to one another. The fluorescence bands were r ecorded with a monochromator, a photomultiplier, and a digitizing osci lloscope controlled by a microcomputer. In addition to the previously reported and analyzed ''blue-band'' fluorescence that can be excited w ith a single laser, we observed short-lived and structured fluorescenc e bands as well as the corresponding excitation bands in the blue spec tral region, which we assigned to transitions between specific states of HgCd. An analysis of the bands yielded the vibrational constants fo r some of the states, as well as their relative internuclear equilibri um separations. These results provide an initial basis for the draft o f a partial potential-energy diagram consisting of spin-orbit states c orrelated to the 5(3)P manifold in Cd.