OVERTONE SPECTROSCOPY OF COMPLEXES OF HYDROGEN FLUORIDE

Abstract

The second overtone spectra of ArHF and $(HF)_{2}$ are obtained by intracavity laser induced fluorescence with a Ti-sapphire ring laser and supersonic slit jet. Fundamental emission $(v =1)$ is monitored using a PbS detector. Sub-Doppler spectra of $(3000)-0, (3100)-0, (3110)-0$. and $(321 0)-O$ transitions of ArHF are recorded. We determine vibrational band origins of $v_{o} = 11339.034, 11412.438$ and $11422.378 cm^{-1}$ and rotational constants of $B = 0.10330, 0.10276, 0.10118 cm^{-1}$ for the $(3000), (3100)$, and (3110) bands and $v_{O} =11484.7$ for (3210). All fit extrapolations of related constants of HF stretching states $v= 0 -2$. Of the quartet $v=3 (HF)_{2} . (v_{1}=3), (v_{2}=3)$ and $(v_{1}=2, v_{2}=1)$ have been seen. Two subbands $K=0$ and $K=1$ are observed for $(v_{1}=3)$, while only $K=0$ is seen for $(v_{2}=3)$ and $(v_{1}=2, V_{2}=1)$. The Interconversion tunneling is quenched in all states. The band origins, rotational constants and predissociation line widths are $\begin{array}{lll} v_{O} = 11273.501cm^{-1}, & B= .22118 cm^{-1} \Delta= 100 MHz K=0, & \Delta= 1900 MHz K=1 (v_{1}=3); \\ v_{O} = 11043.09 cm^{-1}, & B= .2240 cm^{-1} \Delta=104 MHz (v_{2}=3); \\ v_{O} = 11552.8 cm^{-1}, & B= .221 cm^{-1}, & \Delta=1 MHz (v_{1}=2,v_{2}=1).\end{array} $ No discernable variation of predissociation width with J is found. The linewidths are different than expected from simply extending $v=1$ and 2 observations. The results for $(v_{1}=3) K=0$ and $K=1$ can be understood in terms of specific centrifugal distortion interactions.