Equilibrium Distribution of Dimers in Irradiated RNA Molecules

The situation where dimer formation and splitting is possible in irradiated RNA molecules is considered. The equilibrium distribution of dimers ( i.e. the distribution after a long time) is obtained, in particular the average number of dimmers as a function of molecule length and reaction rates. The average equilibrium dimer density is obtained for long chains, and this exact result is compared with earlier approximations to the full problem.