Electron transfer mediated decay in HeLi cluster: Potential energy surfaces and decay widths.

Electron transfer mediated decay (ETMD) is a process responsible for double ionization of dopants in He droplets. It is initiated by producing He in the droplet, which is neutralized by ETMD, and has been shown to strongly enhance the dopant's double ionization cross section. The efficiency of ETMD, the spectra of emitted secondary electrons, and the character of the ionic products depend on the nuclear dynamics during the decay. To date, there has been no theoretical investigation of multimode dynamics which accompanies ETMD, which could help to understand such dynamics in a He droplet. In this article, we consider the He-Li cluster where an ab initio examination of multimode dynamics during the electronic decay is feasible. Moreover, this cluster can serve as a minimal model for Li adsorbed on the droplet's surface-a system where ETMD can be observed experimentally. In He droplets, Li can be formed in both the ground XΣ and the first excited aΣ states. In this article, we present ab initio potential energy surfaces of the electronic states of the He-Li cluster involved in ETMD, as well as the respective decay widths. We show that the structure of these surfaces and expected nuclear dynamics strongly depend on the electronic state of Li. Thus, the overall decay rate and the appearance of the observable electron spectra will be dictated by the electronic structure of the dopant.