Equilibrium constants of nuclear reactions in supernova explosions

We study the change in internal rotational energy in the transformation of protons to neutrons in the beta-decay reactions that take place in the collapse of the iron core of massive stars that precede Type II supernova explosions. We consider an ensemble of electrons, protons, neutrons and neutrinos undergoing beta-decay reactions, treat. the protons and neutrons as triatomic rotors, evaluate the equilibrium constant to obtain the change in rotational energy during the proton-to-neutron transformation. We estimate such change for a variety of conditions, and compare with the energy released in a supernova explosion.