^a Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

^b Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

^c L.D. Landau Institute, Moscow, Russia

^d Laboratory de Physique des Solides (associe au CNRS), Université Paris-Sud., Batimont 510, 91405, Orsay Cedex, France

^e University of Texas, Dallas, TX, USA