Pure rotational spectrum of boron trifluoride–11B observed by microwave Fourier transform spectroscopy

Abstract

Pure rotational transitions of ¹¹BF₃ in the ground vibrational state with Δk=±3 selection rule have been measured between 14 and 17 GHz. The extremely weak transitions have been observed with a pulsed microwave Fourier transform spectrometer. The Q subbranch between k=±1 and ∓2 has been assigned for transitions with J=11 to 50. In addition, an R and a P subbranch have been identified for transitions with J between 17 and 45 and k between 10 and 32. A total of 60 measured transition frequencies has been combined in a least squares fit of the molecular constants B, C−B, D_J, D_JK, D_K, H_J, H_JK, H_KJ, and H_K.