High resolution laser spectroscopy of H-2 at 86-90 nm

A narrowband and tunable extreme ultraviolet laser source was employed to study the absorption spectrum of molecular hydrogen in the range 86-90 nm. Frequencies of transitions to the C-1 Pi(u), upsilon = 6-10, D-1 Pi(u), upsilon = 1, B'(1) Sigma(u)(+), upsilon = 0-2, and B-1 Sigma(u)(+), upsilon = 20, 22, 23, 25, 26, and 27 states were measured. In view of the hypothesis of the C-1 Pi(u) states of H-2 as possible carriers of the diffuse interstellar bands the energies of these states were determined with high accuracy (0.02-0.06 cm(-1)). (C) 1996 Academic Press, Inc.