Knowledge Bank

The infrared and visible $(A-X)$ emission spectra of $\mathrm{<mrow\; data-mjx-texclass="ORD">107<mrow\; data-mjx-texclass="ORD">/</mrow>109</mrow>}$ AgH and $\mathrm{<mrow\; data-mjx-texclass="ORD">107<mrow\; data-mjx-texclass="ORD">/</mrow>109</mrow>}AgD$ have been recorded with a Fourier transform spectrometer. The silver hydride molecules were generated by heating Ag metal to $1050-1325\circ C$ in a high-tempeature furnace containing a few torr of an Ar/H mixture subjected to a 3kV/330mA discharge. The observed spectra consist mainly of rovibronic transitions belonging to the $\Delta v=0,-+1,-+2$ sequences. The higher quality measurements from this study together with previous grating data on the A-X system of AgH, and micrawave data were first treated in a combined isotopomer fit to yield improved empirical molecular parameters for both the ground and first excited electronic states of each species. The A-state potential curve of AgH has an anomalous shape resulting from avoided crossings. In an attempt to better determine the A-state potential curve and its mass-dependent Born-Oppenheimer breakdown parameters, the combined data were directly fitted to potential energy functions.