Dynamical effects on the photo-detachment spectra of Li 4

It is shown that the observed sharp peaks in the photodetachment spectra of Li 4 − can be understood by including the effect of cluster dynamics. Theoretical electronic structure studies show that Li 4 − is marked by doublet rhombus and quartet distorted tetrahedral isomers. By including dynamical effects within a classical picture, it is shown that the observed spectrum can be explained in terms of transitions from rhombus ground state to the singlet neutral configurations. A vibrational analysis is used to identify the modes leading to the observed peaks. Our studies underscore the importance of dynamical effects on the photodetachment spectra.