The 3PI(u)(4 3P, 4 3P) state of the Zn2 excimer was excited by pump-an
d-probe irradiation of Zn vapor in a quartz cell. The resulting struct
ured fluorescence and excitation spectra, which were recorded in the 2
70-290 nm spectral region, are interpreted as arising from 3PI(u)(4 3P
, 4 3P)<-- -->3PI(g)(4 3P, 4 1S) vibronic transitions. An analysis of
the vibrational structures yielded the vibrational frequencies, relati
ve energies, and relative equilibrium internuclear separations for the
3PI(u) and 3PI(g) states.