Rotational spectra of conformers and isotopomers of 1-hydroxynaphthalene

The rotational spectra of cis- and trans-1-hydroxynaphthalene and trans-l-D O-naphthalene have been recorded between 6 and 18 GHz using a pulsed microw ave spectrometer. Most of the transitions detected are a type; hyperfine sp littings from the electric quadrupole interaction were observed for some tr ansitions of the deuterated isotopomer. The frequencies were well modeled w ith an S-reduced asymmetric rotor Hamiltonian. The rotational constants wer e determined much more accurately than previously. In addition, the quartic centrifugal distortion parameters were determined for the first time. Thei r values were very small, consistent with the rigid framework of this aroma tic molecule. Theoretical calculations were carried out to support the assi gnment of the two forms to the cis and trans conformers. These calculations suggested that the cis conformer is slightly nonplanar in its equilibrium configuration, a property which is not inconsistent With its rotational con stants. (C) 1999 Academic Press.