THE 0(U)-X0(G)+ SPECTRUM OF HG2 EXCITED IN A SUPERSONIC JET((6(3)P(1))[)

The 0u+ (6 P-3(1)) <-- X0g+ excitation spectrum of Hg2 van der Waals m olecules, produced in a pulsed free-jet supersonic expansion beam cros sed with a pulsed dye-laser beam, was studied using He as a carrier ga s. A well-resolved structure, arising from transitions between the vib rational levels of the lower and upper states, was recorded at various beam conditions. An analysis of the spectrum yielded the vibrational constants, dissociation energies, and the difference between the equil ibrium internuclear separations for the molecule in the two electronic states.