Infrared Spectroscopy of Interstellar Molecular Hydrogen: Decomposition of Thermal and Fluorescent Components

High-resolution spectroscopic observations of vibrationally excited H2 are reported for nine Galactic sources. Data were obtained using a cooled circular variable filter wheel in tandem with an ambient-temperature Fabry-Perot interferometer on the UKIRT in August 1987. It is found that collisional and fluorescent excitation processes are both evident in most of the sources, although one may be dominant. The ortho/para ratio is determined for sources with fluorescent excitation and found to range from 1.0 to 1.8, in contrast with the high-temperature equilibrium value of 3.