The electronic spectrum of tantalum hydride and deuteride

Abstract

The diatomic molecule tantalum hydride (TaH) and its isotopologue tantalum deuteride (TaD) have been detected for the first time by laser excitation spectroscopy. The gas-phase molecules were produced in a hollow cathode discharge. Two red-degraded bands, one arising from TaH at 636 nm and the other from TaD at 635 nm, have been recorded at sub-Doppler resolution by intermodulated fluorescence spectroscopy. A rotational analysis shows that both bands are Ω = 2←2 in character, with well-resolved Ω-doubling in the upper state of TaH. Analysis of the ¹⁸¹Ta magnetic dipole and electric quadrupole hyperfine structure reveals that the lower X³Φ₂ electronic state of the two transitions arises from a σ²πδ electronic configuration, in agreement with previous theoretical calculations. The bond length in the TaH X³Φ₂ (v = 0) level is found to be 1.756960(4) Å.

Keywords:

• tantalum hydride
• tantalum deuteride
• electronic spectrum
• hyperfine structure

Additional information

Funding

This work was supported by the National Science Foundation [grant number CHE-0844405], [grant number CHE-1265741]. K.J. Manke thanks the Arnold Beckman Foundation for support in the form of a Beckman Scholarship.