Thermodynamic perturbation theory for associating fluids with small bond angles: Effects of steric hindrance, ring formation and double bonding

We develop the first comprehensive approach to model associating fluids with small bond angles using Wertheim's perturbation theory. We show theoretically and through monte carlo simulations that as bond angle is varied various modes of association become dominant. The new theory is shown to be in excellent agreement with monte carlo simulation for the prediction of the internal energy, pressure and fractions in rings, chains, double bonded over the full range of bond angles.