The geometry and complete harmonic force field for the all-trans form of 1,3,5-hexatriene have been determined from ab initio Hartree-Fock calculations. To account for systematic errors, the theoretical force field was scaled by empirical factors taken over fixed from butadiene. The scaled quantum mechanical (SQM) force field obtained this way reproduces the fundamental vibrational frequencies of hexatriene within 20 cm-1 in most cases, which gives a good basis for analyzing the spectral assignment. In the light of a slight discrepancy between theory and experiment for the CC stretching frequencies and bond lengths, the question of how different the two kinds of double bonds in hexatriene are is raised.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry