Spectroscopy of metastable species in a free-jet expansion: The <i>D</i>′←<i>A</i>′ transition of I2

Abstract

The A′2u 3Π state of I2 is observed in a free-jet expansion of I2 in Ar, where it is prepared by ArF laser irradiation. Laser excitation spectra are recorded for 37 bands in the υ′←0″ progression of the D′2g(3P2)←A′ transition. The spectra display rotational temperatures of ∼5 K. At the 0.08 cm−1 resolution of the probe laser, rotational congestion near the band origins necessitates analysis by a nonlinear least-squares contour simulation method. Subsequent correlated fits of the band-by-band results are combined with other results to produce global constants valid for υ′=0–86, υ″=0–32.