CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

known. However, for most of the complex systems, accurate inter-particle potentials are
not known, and hence the evaluation of these quantities becomes difficult. The present
study focuses mainly on the n-dependence of the derived expressions and therefore treats
the coefficients as unknown parameters.
Now the results of numerical calculations carried out using the present formalism
is presented. The procedure to be adopted is to find out the optimum values of and
using calculated values of σ, Eq.(16) or Eq.(27) depending on the range of n, and
the experimental values of ∆E VDE (n ) so that the calculated results are very close to the
experimental values. Using these values of and , ∆E VDE (n ) or ∆E ADE (n) is
calculated based on Eq.(16) or Eq.(27) and plotted in the graph as a function of 1/n or
1/(n+σ) depending on the range of n along with experimental results. On extrapolation of
∆E VDE (n) to cluster of infinite size (n=∞), the bulk detachment energy viz. ∆E DE ∞ is
obtained. Similar procedures are to be adopted to calculate ∆E ADE (n). As an illustrative
example, uni-negative and doubly negative anionic hydrated clusters are considered viz.
. , . , . , . , and . and . ,
respectively. Let us first calculate the volume ratio (V R ) which are 3, 2.5, 2, 2.5, 4 and 4
for the systems, . , . , . , . , . and
. , respectively. Then . cluster is considered, for which experimental
values of ∆E VDE (n) are available for n=20 to 60. 86 Since the clusters are medium in size,
Eq.(16) is used to calculate ∆E VDE (n). The calculated results of ∆E VDE (n) are plotted
against 1/ for these systems along with experimental results in Fig.8.1(A). The best
fitted plot (see Fig. 8.1A) has a correlation coefficient (R) greater than 0.98, showing an
excellent agreement of the calculated values with the experimental results.
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