Laboratory detection and pure rotational spectrum of AlSH (X̃¹A′)

The pure rotational spectrum of AlSH (X̃ ¹A′) has been recorded using millimeter and submillimeter direct absorption techniques. Measurements of its deuterium isotopomer have been recorded as well. This study is the first laboratory detection of this molecule, which was created by the reaction of aluminum vapor and H₂S. Nine and seven rotational transitions of AlSH and AlSD were measured, respectively, each consisting of K_a = 0 through K_a = 6 asymmetry components. From these data, rotational constants have been established. Calculation of an r ₀ structure indicates that AlSH is bent with an angle near 90°. These measurements will enable searches for AlSH to be carried out in circumstellar gas, where aluminum-bearing molecules, as well as H₂S, are present.