Chapter 21: Tunneling of a System with Internal Degrees of Freedom

The problem of tunneling of a system of particles with internal degrees of freedom has not received much attention, although in some important physical systems for example α-decay the decaying part is a composite system. In physics and chemistry of molecules there are observable effects attributable to the tunneling of a molecule from one well to the other in symmetric and asymmetric double-wells [1]–[7]. We have also seen (Sec. 20.5) an attempt to use the tunneling of a molecule as a way of introducing time operator and measuring tunneling time [8].