Centrifugal distortion effects in the microwave spectra of 1,3-dioxane, tetrahydropyran and piperidine

Applying a bootstrap approach to transition assignment, a first-order centrifugal distortion analysis has been performed on 1,3-dioxane, tetrahydropyran, and piperidine (axial NH conformer). Q-branch transition frequencies for J up to 32 have been combined with previously published or remeasured frequencies for low J, R-, and Q-branch transitions to yield values for the quartic centrifugal distortion parameters. Comparison is made between the results obtained using two forms of the quartic Hamiltonian.