The majority of molecules proposed for laser cooling and trapping experiments have Σ-type ground states. Specifically, 2Σ states have cycling transitions analogous to 𝐷1 lines in alkali-metal atoms while 1Σ states offer both strong and weak cycling transitions analogous to those in alkaline-earth atoms. Despite this proposed variety, to date, only molecules with 2Σ-type ground states have successfully been confined and cooled in magneto-optical traps. While none of the proposed 1Σ-type molecules have been successfully laser cooled and trapped, they are expected to have various advantages in terms of exhibiting a lower chemical reactivity and an internal structure that benefits the cooling schemes. Here, we present the prospects and strategies for optical cycling in AlCl—a 1Σ molecule—and report on the characterization of the 𝐴1Π state hyperfine structure. Based on these results, we carry out detailed simulations on the expected capture velocity of a magneto-optical trap for AlCl. Finally, using ab initio calculations, we identify the photodissociation via a 31Π state and photoionization process via the 31Σ+ state as possible loss mechanisms for a magneto-optical trap of AlCl.
