Algebraic approach to vibrational spectra of tetrahedral molecules: a   case study of silicon tetrafluoride
  Both the stretch and bend vibrational spectrum and the intensity of infrared transitions in a tetrahedral molecule are studied in a U(2) algebraic model, where the spurious states in the model Hamiltonian and the wavefunctions are exactly removed. As an example, we apply the model to silicon tetrafluoride SiF$_4$. 
Xi-Wen Hou, Shi-Hai Dong, Mi Xie, and Zhong-Qi Ma