Knowledge Bank

Line assignments in the two H-F stretching fundamentals have been extended considerably over those reported at this meeting last year. Only b-type transitions have been observed for the higher frequency $\nu 1$ band centered at $\sim$$3929cm-1$ while only a-type transitions have been assigned for the $\nu 2$ band at $3866cm-1$. The $K\Delta K=-2,-1,0,+1$, and +2 subbands of the $\nu 1$ band have been assigned. The upper states of the $K\Delta K=1$ subbands of this vibration are perturbed. At this moment only the K = 0 and K = l subbands of the parallel band have been assigned. The molecule is very non-rigid, and it is necessary to fit each subband independently using a Polo formalism. As in other very near prolate top molecules, the asymmetric rotor splitting of the K=2 states has been found to be anomalously large. The inversion splitting in the upper state of both bands is about one third that of the ground state.