On Lennard-Jones type potentials and hard-core potentials with an   attractive tail
  We revisit an old tree graph formula, namely the Brydges-Federbush tree identity, and use it to get new bounds for the convergence radius of the Mayer series for gases of continuous particles interacting via non absolutely summable pair potentials with an attractive tail including Lennard-Jones type pair potentials. 
Thiago Morais, Aldo Procacci, Benedetto Scoppola
math-ph math.MP