DETERMINATION OF BOND LENGTHS OF TRIATOMIC SPECIES USING VIBRATIONAL FREQUENCIES

Structural information on transient species in excited and ionic state s is important for understanding not only their bonding and molecular properties but also the photochemical and photophysical processes invo lved. In this work, the potential energy distribution procedure, Badge r's rule and Hershbach and Laurie's equation were modified and represe nted in the symmetry coordinates instead of internal ones as proposed by other workers. These three methods were applied to determine the st ructural parameters of triatomic molecules in different electronic sta tes. The results obtained are compared with those from experimental wo rk, ab initio calculations and Franck-Condon analyses. The major advan tage of the proposed algorithm in comparison with other theoretical me thods is that it is simple and fast in structure determination, with o nly vibrational frequencies and reference geometries required.