Animation of Imaginary Frequencies at the Transition State

• Robert H. Higgins ^[1]
  1. [1] Fayetteville State University

     Fayetteville State University

     Township of Cross Creek, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 72, Nº 8 (August), 1995, págs. 703-705
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • HyperChem is one of the most useful commercial programs available for optimization of structures, visualization of orbitals, and animation of vibrational spectroscopy on the PC. Despite its obvious strengths, one of its shortcomings involves its inability to perform transition state calculations. We wish to report that transition states found by MOPAC calculations, and imported into HyperChem in z-matrix format and submitted for computations of vibrations, do indeed provide the negative "frequency" (i.e., imaginary frequency) associated with vibration along the reaction coordinate. This animation greatly improves the student's comprehension of stereochemical changes occurring at the transition state.