Fourier Transform Emission Spectroscopy of the E2π--X2Σ+ Transitions of SrH, SrD and BaH.

Emission spectra of SrH, SrD and BaH have been studied at high resolution using a Fourier transform spectrometer. The SrH and SrD molecules have been produced in a high temperature furnace by the reaction of strontium metal vapor with H₂/D₂ in the presence of a slow flow of Ar gas. The spectra observed in the 18000--19000 cm^-1 region consist of the 0--0 and 1--1 bands of the E²π--X²Σ⁺ transition of the two isotopologues. A rotational analysis of these bands has been obtained by combining the present measurements with previously available pure rotation and vibration-rotation measurements for the ground state, and improved spectroscopic constants have been obtained for the E²π state.

The high resolution spectrum of the E²π--X²Σ⁺ transition of BaH has been observed using a Ba hollow cathode lamp operated with 150 V and 300 mA current with a slow flow of 700 mTorr of Ar and 40 mTorr of H₂ gases. The spectrum in the 14000--15600 cm^-1 region was recorded at a resolution of 0.015 cm^-1 with the 1-m Fourier transform spectrometer associated with the McMath-Pierce Telescope of the National Solar Observatory at Kitt Peak. A rotational analysis of the 0--0, 1--1 and 2--2 bands has been performed and improved spectroscopic constants were determined for the E²π state by combining the data with existing vibration-rotation measurements of the ground state.