The potential function for the internal rotation and the derived potentialenergy distribution of the normal modes for 3-chloropropionyl chloride based on ab initio calculations

The conformational behavior and structure of 3-chloropropionyl chloride wer e investigated by ab initio calculations. The 6-311+G** basis set was emplo yed to include polarization and diffuse functions in the calculations at RH F and MP2 levels. The compound was predicted to exist as a complex mixture of stable conformers. The trans-cis conformation with minimum chlorine-chlo rine interaction was predicted to be the lowest energy form for the molecul e. From the potential scan, the barrier for internal rotation between the t rans-cis and trans-gauche conformers was calculated. The vibrational freque ncies were computed at thr HF level. Normal coordinate calculations were ca rried out and potential energy distributions among symmetry coordinates wer e calculated for the stable conformers of the molecule. Raman and infrared spectra of both the individual conformers and the mixture of them were comp uted at 300 K. (C) 1999 Elsevier Science B.V. All rights reserved.