Electron cavity formation in solid helium

In this paper we consider a trapping mechanism for excess electrons in solid helium. Structural modifications are energetically favored in this system resulting in the localization of the excess electron in an expanded cavity of a radius of ∼ 9. The optical and the transport properties of this trapping center are qualitatively examined. A pressure induced transition from the localized to the delocalized state of the excess electron is considered.