On the pure rotational spectrum of BF3 in its vibronic ground state

Abstract The centrifugally induced pure rotational absorption spectrum of BF 3 in its vibronic ground state has been computed using the theory of Watson. Maximum absorption of order 10 −5 (mol/liter) −1 cm −1 is found to occur in a frequency region around ∼30 cm −1 . Due to the coincidence of the Q and R branches the full spectrum exhibits an intensity alternation of the individual lines which is not present in the case of T d molecules studied previously; it could facilitate the experimental detection of the spectrum.