Double first-order model parameters

Table V. Double First- Order Model Parameters and Fit Variance ...

The model fit variances are given in Table IV and calculated rate parameters for the two reactions in Table V. In nearly all cases an improvement in model fit was observed. This is typified by the comparison between the fit gg a single first-order and double first-order (DFO) model to the 0 Co data, as shown in Figure 5. Although the DFO model shows considerable improvement over single-site models, residual plots indicate a small systematic deviation at higher concentrations. This is discussed further in the following section. 

The properties of a polymer solution become extremely complex in the vicinity of the Flory temperature TF, when the size of the chains increases. In fact when N -+ oo, Tc - Tf. Then, the system becomes critical in a double manner. First, a system made of very long chains is equivalent to a Landau-Ginzburg model, in which the order parameter is a zero component vector (n = 0). Secondly, the top of the demixtion curve, even for chains of finite length, is a critical point, and near this point the system can be described by another Landau-Ginzburg model the order parameter of which is a one-component vector (n = 1). 

---