In this work, we have used theoretical ab initio calculations to design a molecular trap for an excess electron consisting of two chains of hydrogen-bonded HF molecules and a water molecule. A system with a 'tweezers'-type shape has been found, where the excess electron is localized between two HF molecules in a (...)FH(.)e(.)HF(...) bridge. (C) 2003 Elsevier B.V. All rights reserved.