Knowledge Bank

The vibrational spectrum of cyclo-$C8$ in an argon matrix at ten degrees Kelvin has been identified for the first time by Fourier transform infrared spectroscopy. Vapors, from solid/powder carbon vaporized in an oven cycled between 1700-3000 K during the deposition process, were co--condensed with argon on to a Csl substrate maintained at 10 K.A frequency measured at $1694.7cm-1$ has been assigned to the $\nu e(e\prime )$ C-C stretching fundamental of cyclic-$C6$. This assignment is supported by $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C$ isotopic data and is in good agreement with quantum chemical predictions.