Knowledge Bank

Making use of large-scale CCSD(T)-$calcualtions1$ the equilibrium geometry of $C5$ was calculated to be linear with $R1e$ (outer CC) = 1.28959 {\AA} and $R2e$ (inner CC) = 1.28190 {\AA}, with uncertainties of ca 0.0005 {\AA}. The corresponding equilibrium rotational constant is $Be$ = 25550.6 MHz in good agreement with an approximate experimental value of 2548.7 $MHz.2$ Analogous calculations of $C3$ yield a linear equilibrium structure with $Re$ = 1.29431 {\AA} for $C2$ a value of 1.24209 {\AA} is obtained. The latter differs from $experiment3$ by 0.0004 {\AA}.