ANALYSIS OF HIGH RESOLUTION INFRARED SPECTRA OF 1,1-DICHLOROETHYLENE IN THE $500 - 1000$\ \wn\ RANGE

Abstract

The far infrared beamline of the Canadian Light Source synchrotron facility has been used to record three rotationally resolved vibrational bands of 1,1-dichloroethylene in the $500-1000$ cm$^{-1}$ range, at $0.00096$ cm$^{-1}$ resolution. These correspond, for the H$_2$C$=$C$^{35}$Cl$_2$ isotopologue, to an $a$-type band (CCl$_2$ antisymmetric stretch) at $796.0$ cm$^{-1}$, a $b$-type band (CCl$_2$ symmetric stretch) at $603.0$ cm$^{-1}$, and a $c$-type band (CH$_2$ wag) at $868.6$ cm$^{-1}$. Anharmonic frequency calculations at the MP2/6-311++G(2d,2p) level, combined with rotational and centrifugal distortion constants from a millimeter wave study of the ground state, nderline{\textbf {50a}}, (1995), 347-351.}, were an invaluable aid in facilitating the spectroscopic assignment for this asymmetric top (${\kappa} = -0.58$). Analysis of the $796$ cm$^{-1}$ band is nearly complete, giving well determined excited state rotational and centrifugal distortion constants. Results of this analysis and progress with analysis of the other two bands will be presented.