Knowledge Bank

We have observed AlSH and AlSD for the first time using the technique of Fourier transform microwave spectroscopy. AlSH (AlSD) was produced in supersonic free jet expansions by reaction of $H2S$ $(D2S)$ with laser ablated Al atoms. The spectral search was guided by an ab initio computional prediction performed prior to the experiments. The lowest frequency rotational transition, $101-000$, was measured and the hyperfine structure due to the nuclear spin of $\mathrm{<mrow\; data-mjx-texclass="ORD">27</mrow>}Al$ was analyzed. By comparing the obtained rotational constant, $12(B+C)$, with the computational prediction, it was concluded that AlSH has a bent structure with a bond angle close to $90\circ$. Using the nuclear electric quadrupole and nuclear spin-rotation coupling constants obtained, the electronic structure of AlSH was investigated.