PULSED DISCHARGE JET SPECTROSCOPY OF DSIF AND THE EQUILIBRIUM MOLECULAR-STRUCTURE OF MONOFLUOROSILYLENE

The jet-cooled laser induced fluorescence excitation spectrum of the ( A) over tilde (1)A '' - (X) over tilde (1)A' band system of DSiF has b een observed using the pulsed discharge jet technique. Vibrational ana lysis of the spectrum yielded upper state harmonic vibrational frequen cies of omega(1) = 1322, omega(2) = 444, and omega(3) = 867 cm(-1). Vi bronic bands involving all, of the upper state fundamentals of HSiF an d DSiF have now been rotationally analyzed, allowing a determination o f the excited state equilibrium structure as r(e)'(SiH) = 1.526 +/- 0. 014 Angstrom, r(e)'(SiF) = 1.597 +/- 0.003 Angstrom, and theta(e)'(HSi F) = 115.0 +/- 0.6 degrees. The harmonic frequencies and centrifugal d istortion constants were used to obtain harmonic force fields and aver age (r(z)) structures for the ground and excited states. The ground st ate average structure was used to estimate the equilibrium structure o f r(e) ''(SIH) = 1.528 +/- 0.005 Angstrom, r(e) ''(SiF) = 1.603 +/- 0. 003 Angstrom, and theta(e) ''(HSiF) = .96.9 +/- 0.5 degrees. (C) 1997 American Institute of Physics.