Knowledge Bank

The $J=0\to 1,1\to 2$, and $2\to 3K=0$ rotational transitions have been observed for several isotopic species of the Ne-HCN dimer. Rotational constants obtained by fitting the line centers are listed below. [FIGURE] $\chi aa(21Ne$), the hyperfine interaction constant for $\mathrm{<mrow\; data-mjx-texclass="ORD">21</mrow>}Ne$, was found to be -0.246 MHz in the $J=0\to 1$ transition of $\mathrm{<mrow\; data-mjx-texclass="ORD">21</mrow>}Ne-HC15N$. The value of $\chi aa(14N)$ in $\mathrm{<mrow\; data-mjx-texclass="ORD">20</mrow>}Nc-HC14N$ is highly dependent on J being $-0.982,-1.034$, and $-1.109$ MHz for $J=1,2,3$ respectively. A number of $K\ne O$ transitions have also been observed including what appears to be inversion doubling of the $111\to 212$ transition. The Stark effect has been observed for several transitions and differs from that predicted for a linear species. Our results indicate that Ne-HCN is even more highly nonrigid than $Ar-HCN,1$ with even stronger angular-radial coupling in the interaction $potential.2,3$ Kr-HCN, on the other hand, is more ``normal” than $either.4$.