EFFECT OF THE PLOTTING PARAMETER 'K' UPON LIGHT-SCATTERING RESULTS,

The optimization of the Zimm grid fit, as applied to the scattering of light from dilute polymer solutions, is discussed as a function of the plotting parameter k. The characteristic parameters of the polymer and of its solution are relatively insensitive to the choice of k however, it is shown by a detailed error analysis, that a theoretically predictable value of k minimizes the ratio of a function of error of the independent variable a linear combination of the concentration and of a function of the scattering angle to the same function of error of the dependent variable the reciprocal intensity function. Optimal fit is obtained by choosing a value of the plotting parameter k such that, on the average, the error committed on the independent variable is less than one percent of that committed on the dependent variable. It is thus shown that k is not arbitrary, but that a predictable value can optimize the fit of the grid. Author