Knowledge Bank

We have found that subbands in the C-type band at $897.950cm-1$ in the high resolution infrared spectrum of trans-1,2-dichloroethylene can be analyzed separately for the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl37Cl$ isotopomers in natural abundance with the aid of the Giessen Loomis-Wood program. Consequently, it is unnecessary to synthesize isotopically pure chlorine species in order to determine the structure of this nonpolar molecule by high resolution infrared spectroscopy. For the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl2$ isotopic species 874 ground state combination differences (GSCD) have been fitted to a Watson-type Hamiltonian. The GS rotational constants are $A=1.7472665(55).B=0.5157118(5)$, and $C=0.5008142(5)$ $cm-1$ with $\kappa =-0.9982$. Based on the GS constants a preliminary comparion with the structure of the cis isomer will be made. Work on the analysis of the corresponding bands of the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl37Cl$ species and the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl2-d2$ species is in process