Knowledge Bank

Using a free jet expansion which incorporates a heated nozzle we have recorded the laser excitation spectrum of NICI2 at low rotational temperatures isotope shifts have been resolved which permit the assignment of the progressions involving the symmetric stretching vibrational mode $(\omega \prime =357.69(5)1cm-1,\omega 1\prime \prime \approx 360cm-1$). Sequence bands involving the bending vibrational mode have been assigned. A triplet splitting attributable to fine structure effects has also been observed. Work at higher resolution confirms the assignment of the $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}Cl/37Cl$ isotope structure from the observed intensity alternation. Rotational analysis of the 1(1-0) bands $(F1$ and $F2)$ allows the splitting due to the Ni isotopes $(58Ni/60Ni/62Ni)$ to be identified and a parity doubling parameter to be determined. ($F2$ band $B\prime \prime =0.056793(l3)cm-1B\prime \prime =0.054779(13)cm-1qeff=0.1083(16)cm-1)$