\title{\normalsize ANORMALOUSLY ENHANCED SCREENING POTENTIAL OBSERVED\\ IN COLLISIONS OF NOBLE GAS IONS ON CARBON ATOMS IN $C_{60}$\\ \vspace{20pt} I. Arai$^{\ast}$, T. Miura$^{\ast}$, M. Imanaka$^{\ast}$, H. Sasaki$^{\ast}$, S. Tomita$^{\sharp}$ and S.M. Lee$^{\ast}$\\ \vspace{20pt} $^{\ast}$Institute of Physics, University of Tsukuba, Ibaraki 305, Japan\\ $^{\sharp}$CEA Grenoble, Service des Ions, Atomes et Agregates, 17 rue des Martyrs 38054,\\ Grenoble Cedex 9, France\\ \vspace{10pt} \begin{quote} Collision dynamics of noble gas ions $He^{+}$, $Ne^{+}$, $Ar^{+}$ and $Xe^{+}$ on carbon atoms in $C_{60}$ at incident energies from $3.2 keV$ to $9.8 keV$ has been studied. Measured cross sections have shown anormalously enhanced screening which could not be accounted for by well-known Moli\`{e}re's potential. Effective potentials have been evaluated so as to fit the cross sections. Extra screening factors are found to be Wood-Saxon type functions. Substantially new interaction mechanism is suggested. \end{quote} }