Electronic Spectroscopy and Photoionization of LiBe

LiBe has been the subject of several theoretical investigations and one spectroscopic study. Initially, these efforts were motivated by interest in the intermetallic bond. More recent work has explored the potential for producing LiBe and LiBe+ at ultracold temperatures. In the present study, we have advanced the spectroscopic characterization of several electronic states of LiBe and the ground state of LiBe+. For the neutral molecule, the 12Π, 22Σ+, 32Σ+, and 42Π(3d) states were observed for the first time. Data for the 22Σ+–X2Σ+ transition support a theoretical prediction that this band system is suitable for direct laser cooling. Photoelectron spectroscopy has been used to determine the ionization energy of LiBe and map the low-energy vibrational levels of LiBe+ X1Σ+. Overall, the results validate the predictions of high-level quantum chemistry calculations for both LiBe and LiBe+.