Knowledge Bank

The analysis of the microwave spectra of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CF2\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}NCl$ resulted in a quadrupole coupling tensor with $\chi ab=64.54(15)MHz$ and $\chi x=-104.18(13)MHz$ for $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl$. The results from the analysis for $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CF2\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NCl$ were 62.79(105) and -102.78(84) MHz, respectively. In the original work on $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CF2\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NCl1,\chi ab$ could not be increased to above 52 MHz and $\chi x$ not decreased to below -94.7 MHz despite all efforts. The reason for the discrepancy was found in the way that the quadrupole splittings were calculated. The original $calculation1$ did not take into account the matrix elements off-diagonal in $F1$, the approximate quantum number from the coupling of J and $ICl$. The analysis of the spectra of the isotopic species was made with the program modified to include all matrix elements of the exacl Hamiltonian for the exact quantum number F < 35/2 (from the coupling of $F1$ and $IN$). The results of the reanalysis of the $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CF2\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NCl$ will also be given and the important consequences for the molecular structure will be discussed.