Knowledge Bank

The $v2(A1)$ and $v5$ (E) fundamental bands of isotopically pure $H3Si79$ Br, centered at 929.752 and $946.427cm-1$ respectively have been analyzed from a high resolution Fourier transform spectrum in order to improve a former $work1$. These two bands strongly interact through a X-Y Coriolis resonance. We also included in the model the weak Coriolis resonance between $v5$ and $2v3$, with a crossing near $k\ell =-13$ and K = 14, the r-type $\ell (2.-1)$ resonance between $k\ell =2$ and $k\ell =-3$ of $v5$, with a crossing at J = 58 and the accidental resonance $\ell (1.-2)$ between the $(k\ell =1.A2)$ levels of $v5$ and $(K=3,A2)$ of $v2$. We made a global fit of 4200 wavenumbers for $v2$ and $v5$ and 630 upper state energies of $v3=2$, deduced from previously $determined2$ transitions of $2v3-v3$ and of $v3$. A few perturbation allowed transitions were also included in the fit, which gives a s. d. on residuals better than $0.00015cm-1$. A set of molecular parameters for all levels involved will be reported.