XUV-laser spectroscopy of HD at 92-98 nm.

Sub-Doppler excitation spectra of HD have been recorded in the range 9298 nm with the use of a narrow-band and tunable extreme ultraviolet laser in combination with a molecular beam. Frequencies of 147 transitions to the B 1u+, C 1 u, and EF 1g+ states have been calibrated with an average absolute accuracy of 0.035 cm-1. The data have been analyzed in the framework of a semiempirical deperturbation model involving mutual couplings between nearby lying levels of the B 1u+ and C 1 u states. Also, symmetry-breaking effects, i.e., interactions with EF 1g+ gerade states, were inferred from the data. © 1995 The American Physical Society.