Knowledge Bank

The infrared vibration-rotation bands of SeH have been measured in the $X2\Pi$ ground state using a Fourier transform spectrometer. The bands were observed in a microwave discharge of a mixture of $H2$ and Se in the presence of He. The rotational structure of the 1-0, 2-1, 3-2 bands of the $X2\Pi 3/2$ spin component and the 1-0 band of $X2\Pi 1/2$ spin component has been observed in the $1800-2600cm1$ region. The spectroscopic constants for the ground state of SeH have been determined from a fit where the spin orbit coupling constant $A0$ was fixed to the value obtained from the analysis of the infrared laser magnetic resonance data [Ashworth & Brown, J. Chem. Soc. Faraday Trans. II 86, 1995 (1990)]. The principal ground state molecular constants obtained are: and This work is the first determination of the equilibrium molecular constants of the $X2\Pi$ state of SeH.