Electronic Spectroscopy and Photoionization of LiMg

Abstract

Dimers consisting of an alkali metal bound to an alkaline earth metal are of interest from the perspectives of their bonding characteristics and their potential for being laser cooled to ultracold temperatures. There have been experimental and theoretical studies of many of these species, but spectroscopic data for LiMg and the LiMg+ cation are sparse. In this study, rotationally resolved electronic spectra for LiMg are presented. The ground state is confirmed to be X12Σ+ and observations of low-lying electronically excited states are reported for the first time. Reexamination of transitions in the near-UV spectral range indicates that previous band assignments should be revised. Two-color laser excitation techniques were used to determine an ionization energy of 4.7695(4) eV. This value is 1.2 eV below the previously reported experimental estimate. Vibrationally resolved spectra were obtained for LiMg+, yielding molecular constants that were consistent with a substantial strengthening of the bond on ionization.

Electronic Spectroscopy and Photoionization of LiBe

“…The ionization energy (IE) of LiBe and the vibrational structure of the ground-state LiBe + ion have been examined using pulsed-field ionization–zero kinetic energy (PFI-ZEKE) photoelectron spectroscopy. This study closely parallels our recent work on LiMg/LiMg + …”

“…In our recent study of LiMg, band systems in the near-UV spectral range were examined using RE2PI, LIF, and DLIF techniques . The DLIF spectra provided a means for observing the low-energy 1 2 Π state.…”

“…The techniques used to characterize LiBe consisted of LIF, dispersed LIF (DLIF), resonance-enhanced two-photon ionization (RE2PI), photoionization efficiency (PIE), and PFI-ZEKE spectroscopy. 22 Gas-phase LiBe was obtained by laser ablation of the surface of a Li-coated Be rod. The Li coating was applied by rubbing samples of Li metal against the surface of the 6.35-mm-diameter Be rod.…”

“…In our recent study of LiMg, band systems in the near-UV spectral range were examined using RE2PI, LIF, and DLIF techniques. 22 The DLIF spectra provided a means for observing the low-energy 1 2 Π state. To facilitate similar measurements for LiBe, we examined excitation spectra occurring in the 29 000−31 750 cm −1 range.…”

Electronic structure, cold ion–atom elastic collision properties and possibility of laser cooling of BeCs+ molecular ion

“…A series of experiments have been planned in the group of Heaven et al at Emory University to characterize alkali/alkaline-earth dimers using LIF, dispersed LIF (DLIF), RE2PI, photoionization efficiency (PIE) and PFI-ZEKE spectroscopy techniques. 33 They have already started investigations of several alkali/alkaline-earth ionic and neutral dimers by laser ablation. This technique was used in their recent published work for MgLi/MgLi + 33 and BeLi/BeLi + 32 (in preparation) dimers.…”