Rotational spectra in seven excited vibrational states of 1,2,3,4-tetrahydroquinoline

Abstract In this study, more than 7000 rotational line frequencies in vibrationally excited states (ν57, ν56, 2ν57, ν57 + ν56, ν55, 3ν57, ν54) of THQ were measured, assigned and analyzed. The line assignments were facilitated by the Loomis-Wood, Fortrat and other specific diagrams. The rotational transition frequencies were least-squares fitted to sextic A-reduced Hamiltonians. Based on the analyses, the rotational and centrifugal distortion constants of the above-mentioned excited vibrational states were determined with very high accuracies.