Rovibrational spectroscopy of the upsilon(5)=1 level of (SiDF3)-Si-28

The nu(5) fundamental band of trifluorosilane-d (SiDF3) at 627 cm(-1) was s tudied for the first time by high-resolution FTIR spectroscopy at a resolut ion of 2.4 x 10(-3) cm(-1). The analysis was performed simultaneously with available microwave and newly measured submillimeter-wave data in the appro ximation of an isolated degenerate fundamental level of a C-3 nu symmetric top molecule leading to a standard deviation of 0.22 x 10(-3) cm(-1) for th e reproduction of the infrared wavenumbers, 36 kHz for the microwave, and 1 98 kHz for the submillimeter-wave frequencies, respectively. The unitary eq uivalence between the two reductions (Q and D) of the effective Hamiltonian applied in the analysis is demonstrated. (C) 2000 Academic Press.