Ab initio torsional potential and transition frequencies of acetaldehyde.
High-level ab initio electronic structure calculations, including extrapolations to the complete basis set limit as well as relativistic and diagonal Born-Oppenheimer corrections, resulted in a torsional potential of acetaldehyde in its electronic ground state. This benchmark-quality potential fully reflects the symmetry and internal rotation dynamics of this molecule in the energy range probed by spectroscopic experiments in the infrared and microwave regions. The torsional transition frequencies calculated from this potential and the ab initio torsional inverse effective mass function are within 2 cm(-1) of the available experimental values. Furthermore, the computed contortional parameter rho of the rho-axis system Hamiltonian is also in excellent agreement with that obtained from spectral analyses of acetaldehyde.
Department of Theoretical Chemistry, Eotvos University, P.O. Box 32, H-1518 Budapest 112, Hungary.
Attila G
AG
Csaszar
Viktor
V
Szalay
Maria L
ML
Senent