Ionization potential of astrophysically important molecules

Some formulae relating electronegativity differences, ionization potentials and dissociation energies for astrophysically important molecules are prop osed. The relations are as follows: I-AB = (I) over bar(AB) + 0.143e(1.15 chi) (when (I) over bar(AB) < I-AB), I-AB = (I) over bar(AB) + 0.54(D-AB -(D) over bar(AB)) (when (I) over bar(A B) < I-AB), I-AB = (I) over bar(AB) - e(0.8 Delta chi) (when (I) over bar(AB) > I-AB), I-AB = (I) over bar(AB) - 1.85(D-AB - (D) over bar(AB)) (when (I) over bar( AB) > I-AB), where (I) over bar AB, = (IAAIBB)(1/2) and (D) over bar(AB) = (DAADBB)(1/2) . I-AA and I-BB are the ionization potentials and D-AA and D-BB the dissoci ation energies of homonuclear molecules of the corresponding atoms of the h eteronuclear molecule. D-AB represent the dissociation energy of the hetero nuclear molecule and Delta chi the Pauling electronegativity difference. Th e estimated ionization potentials are in good agreement with the values cit ed in the literature. (C) 2000 Elsevier Science Ltd. All rights reserved.