Knowledge Bank

The $\nu 3$ asymmetric stretch rovibrational spectrum of $C5$ has been observed by diode laser absorption spectroscopy of laser vaporized graphite in a free jet expansion.$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ The frequencies for the transitions P(40) through R(30) were measured and fit to obtain $V3---2169.4404(18)cm-1.B0---0.085305(31)$, and $B1-0.084900(22)$. These results are consistent with prior ab initio $calculations2$ indicating the molecule to be linear with slightly inequivalent C-C bond lengths. The results are also consistent with the vibrational frequency obtained from matrix $studies.3$ This technique should be generally applicable to the determination of molecular structures and potential energy surfaces for clusters of refractory elements. This, in turn, will permit us to teast theoretical studies of these complex systems and elucidate the role of these molecules in interstellar space and other contexts.