System-bath coupling complex

Within a permrbative approach, which is second order in the system-bath coupling, the entire bath dynamics enters into the system dynamics via the complex bath correlation function, defined by... 

The behavior of complex dynamical systems can be analyzed and represented in a number of ways. Figure 1 represents one such approach, a constraint-response plot. A constraint, in this case [A], is any variable which the experimenter can control directly. A response, [X]ss in this case, is a measurable property of the system which depends upon the constraint values. The constraints are the external variables, e.g., the temperature of the bath surrounding the reactor or the reservoir concentrations, while the responses are the internal variables, e.g., the temperature or concentration of species in the reactor. The phase trajectory diagram of Fig. 4 is one type of response-response plot. Obviously, in a complex system, there will be several constraints and responses subject to independent (or coupled) variation. 

Direct coupling of a G protein to the heart K+ channel activated by muscarinic ligands was demonstrated in a cell-free system using inside-out patches. Addition to the bath (the cytoplasmic face of the patch) of GTPyS leads, after a lag, to permanent activation of K+ channels [144]. Similarly, addition of purified PTX-sensi-tive G protein from human erythrocytes (referred to originally as Gj ) or its a subunit complexed with GTPy and free of /3y subunits, also stimulates these channels, provided the G protein is preactivated by GTPyS [145]. These results defined the existence of a Gk and identified it physically as an ajSy heterotrimer and a PTX substrate. 

Study the dissociation dynamics of such a system, the development of simple models can best be accomplished using semiclassical or classical techniques. In Section IV C a curve-hopping model is developed, based on a collisional reorientation of the electronic angular momentum. It assumes that a bath atom collides with just one of the diatoms and reorients its electronic angular momentum on a time scale that is short compared to the relative motion of the diatoms. The model is applied to iodine photodissociation dynamics in Section IV D. The dissociation dynamics of polyatomic systems with their internal degrees of freedom is more complex than for diatomics. If these degrees of freedom are not thermally equilibrated and are coupled to the dissociation coordinate, then their dynamics cannot simply be projected out, but rather they can act as an indirect source of excitation of the dissociation coordinate. 

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