Experimental and theoretical investigation of the B∼1A′-X∼1A′ electronic transition of CuSH

►The jet-cooled electronic spectrum of CuSH and CuSD near 430nm has been measured. ► An efficient method for producing metal hydrosulfides in the gas-phase is suggested. ► Calculations on several states of CuSH using the EOM-CCSD approach are reported.► All features of both isotopologues are assigned on the basis of the calculations.