Ab Initio Calculations of Torsionally Mediated Hyperfine Splittings in E States of Acetaldehyde
Li-Hong Xu, E. M. Reid, B. Guislain, Jon T. Hougen, Eugene A. Alekseev, I. Krapivin
Quantum chemistry packages can be used to predict with reasonable accuracy spin-rotation hyperfine interaction constants for methanol, which contains one methyl-top internal rotor. In this work we used these same packages to calculate components of the spin-rotation interaction tensor for acetaldehyde. We then use torsion-rotation wavefunctions obtained from a fit to the acetaldehyde torsion-rotation spectrum to calculate the expected magnitude of hyperfine splittings analogous to those observed at relatively high J values in the E symmetry states of methanol. We find that theory does indeed predict doublet splittings at moderate J values in the acetaldehyde torsion-rotation spectrum that closely resemble those seen in methanol, but that the factor of two decrease in hyperfine spin-rotation constants compared to methanol, puts even the largest of the acetaldehyde splittings a factor of two below presently available Lamb-dip resolution.
, Reid, E.
, Guislain, B.
, Hougen, J.
, Alekseev, E.
and Krapivin, I.
Ab Initio Calculations of Torsionally Mediated Hyperfine Splittings in E States of Acetaldehyde, Journal of Molecular Spectroscopy, [online], https://doi.org/10.1016/j.jms.2017.06.008, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923320
(Accessed December 9, 2023)