On the possibility of a double-well potential formation in diamond-like   amorphous carbon
  A microscopic model, which describes specific features of the electronic spectrum of various allotropic forms of amorphous carbon as being responsible for their structure peculiarities, is presented. It is shown that the formation of a double-well potential is a possible driving force for this behavior. 
A. Rakitin, M.Ya. Valakh, N.I. Klyui, V.G. Visotski, and A.P.   Litvinchuk