Diode laser spectroscopy of the <F>ν8</F> band of the SF<F>5</F>Cl molecule

Diode laser spectra of SF<F>5</F>Cl have been recorded in the <F>ν8</F> band region at a temperature of ca. 240 K, a pressure of 0.25 mbar and an instrumental bandwidth of ca. 0.001 cm<F>-1</F>. Four regions have been studied: a first one in the <F>P</F>-branch (906.849–907.687 cm<F>-1</F>), a second one in the <F>Q</F>-branch (910.407–910.944 cm<F>-1</F>), and two other ones in the <F>R</F>-branch (913.957–914.556 and 917.853–918.705 cm<F>-1</F>).The whole <F>ν1/ν8</F> dyad of SF<F>535Cl</F> has been previously recorded in the group of Professor H. Bürger in Wuppertal, thanks to a Fourier transform infrared spectrometer [J. Mol. Spectrosc. 208 (2001) 169]. These data have thus been combined with our diode laser ones in the aim of refining the analysis. We used an effective Hamiltonian developed up to the fourth order and a set of programs called <F>C4v</F>TDS. One thousand three hundred and forty-six transitions for <F>ν1</F>, 495 (FTIR: 351; diode laser: 144) transitions for <F>ν8</F>, and 406 ground state combination differences have been assigned and fitted. A global fit has been obtained with a rms of 0.00081 cm<F>-1</F> for the <F>ν1</F> band, 0.0012 cm<F>-1</F> for the FTIR data of the <F>ν8</F> band, 0.00055 cm<F>-1</F> for the diode laser data of this same band, and 0.00064 cm<F>-1</F> for the ground state. It appears that more data (for instance, using a supersonic jet) are still necessary to obtain a completely satisfactory analysis of the <F>ν8</F> region. [Copyright &y& Elsevier]