King plot

A by-product of the isotope shift measurements on long isotopic chains and in different transitions is the possibility of drawing King plots of mprecedented accuracy. These provide an extremely sensitive test of the validity of Eq. (26), which implies that the isotope shifts in different transitions, multiplied by the inverse mass shift factor AA /(A - A), or more precisely m ), depend linearly on each other. This... 

One remark is due here about the validity of the King plot procedure, usually employed to check the consistency of isotope shifts in two different electronic transitions. The hyperfine-induced magnetic contribution to the isotope shift has the consequence, that shifts between pairs of even (1=0) nuclei and shifts between even and odd (l= =0) nuclei no longer lie on a straight line. However, after correcting for the hyperfine-induced shift, the validity of the linear relationship between the isotope shifts in two transitions is restored. Hence, any deviation from the King plot of shifts that involve odd nuclei can be taken as strong evidence for the existence of hyperfine-induced shifts. 

In summary, a combination of the plot based on equation (10.6), using any single substance, and determination of the asymptote (10.14), using any pair of substances, provides a sound means of evaluating the parameters K, tC and. Having found these, further experimental points on (10.6) and (10.15), and possibly also (10.7), provide a check on the adequacy of the dusty gas model. Provided attention is limited to binary mixtures, this check can be quite comprehensive. In their published paper Gunn and King... 

Finally, one can also perform a complete analysis by integrating the TPD curves, and finding sets of rates and temperatures corresponding to the same coverage. Such data can be plotted in the form of Arrhenius plots. Hoivever, this is both tedious and time-consuming, and has rarely been performed. [D.A. King, Surf. Sci. 47 (1975) 384]. 

Pickering and Eckstrom evaporate catalyst metals, such as rhodium or nickel, onto the mirrors of a White multiple (20-40) reflection cell (68). A series of scans are taken before and after adsorption of the gases. The comparison of the two sets of curves is accomplished by a method described by King et al. (69), in which the detector output is fed to an ana-log-to-digital converter for recording on punched cards. The final graphs are plotted with an IBM accounting machine. This technique makes it possible to study absorption bands of the order of 0.03 to 0.05% of the radiation. 

Lockett (12) and King (126) noted some theoretical sense in O Connell s correlation. Higher viscosity usually implies lower dif-fusivity, and therefore, greater liquid phase resistance and lower efficiency (12). Higher relative volatility increases the significance of the liquid phase resistance [Eq. (7.13)), thus reducing efficiency (126), Lockett expressed the O Connell plot in equation form... 

Figure 18 Plot of initial chemisorption probability, S0, vs. the incident translational energy for CH4 on Pt(l 1 0)-(l x 2) at Ts = 400 K. 0 = 0°, for a number of different nozzle temperatures. Data adapted from Walker and King [61].

The correlation of log kobs with H or J for the isotopic exchange of molecular hydrogen (Symons and Buncel, 1973) illustrates the difficulties that can arise in such procedures. The relevant plots, shown in Fig. 11, do not readily distinguish between the mechanism involving proton transfer (Wilmarth, 1953) and that in which an addition complex is formed (Ritchie and King, 1968). 

Fie- 19 A plot of logarithms of Kekule counts, In K(B) s of a homologous series of benzenoids and the connectivity indices of the corresponding caterpillar trees (L -Lg). The equivalent king boards are drawn to the left of the° correlation line The numbers in parentheses are the individual Kekul counts ... 

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