The geometries and vibrational patterns of LiClO3 and NaClO3 ion pairs: an ab initio SCF study

✍ Scribed by F. Ramondo; L. Bencivenni; F. Grandinetti

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 594 KB
• Volume: 173
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)87253-n

✦ Synopsis

Ab initio SCF calculations at the 3-2 I G* and 6-3 1 G* HF-SCF level were performed on LiCIOs and NaClOs. Tridentate, bidentate and monodentate coordination models were examined and the bidentate and tridentate structures were characterized as the two lowest-energy minima on the corresponding potential energy surfaces. In particular, bidentate tiClO is favoured by 4 24 kJ mol-' at the 6-3 1 G* level with respect to the tridentate isomer. On the contrary, the tridentate NaClO, isomer is more stable than the bidentate by 127 kJ mol-I. Correlation energies were calculated via Meller-Plesset perturbation theory carried to the second and third order on the bidentate and tridentate energy minima of the two molecules and the bidentate structures of LiCIOs and NaCiOs were determined to be more stable by a 17 and z 3 kJ mol-', respectively with regard to the corresponding tridentate models. The results of MP2/6-31G* and MP3/6-3lG* calculations and the effect of zero-point energy on the stability of the bidentate and tridentate molecules are discussed. Calculated harmonic frequencies of the stable isomers of LiCIOj and NaCIO, and "Cl and 'a0 frequency shifts are reported.