NEAR-DISSOCIATION EXPANSION REPRESENTATION OF LARGE DATA SETS: $B(^{3}\Pi_{Ou}^{+}$) STATE $I_{2}$

$^{1}$A.R. Hashemi-Attar, C.L. Beckel, W.N. Keppin and S.A. Somnleitner, J. Chem. Phys. 70, 3881 (1980). $^{2}$A.R. Hashemi-Attar, C.L. Beckel, J. Chem. Phys. 71, 4596 (1980). $^{3}$R.J. Le Roy and W.-H. Lam, Chem. Phys. Lett. 71, 544 (1980). $^{4}$J.W. Tromp and R.J. Le Roy, Can. J. Phys. 60, 26 (1982).It has been demonstrated that ""near-dissociation expansions"", empirical functions constrained to have the correct theoretically predicted limiting behaviour at dissociation, provide representations of individual sets of vibrational, rotational or centrifugal distortion constants of diatomic molecules which are usually much more compact than comparable Dunham $(\upsilon + l_{5})$ expansions, and which always provide much more reliable extrapolations beyond the range of available experimental $data^{1-4}$. Through application to the extensive Gerstenkorn-Luc data for the B-X system of $I_{2}$, the present work illustrates the utility of these expansions for providing compact and accurate representations of very large data sets. These results suggest that near-dissociation expansions should virtually always be used in place of traditional $(\upsilon + L_{2})$ expansions for summarizing spectroscopic data