Knowledge Bank

“The fundamental frequencies as well as numerous combinations and overtones of $NCO-$ have been observed in single crystals of KI, KBr, KCI, and NaCI in which the cyanate ion is present to the extent of a few tenths of a percent. Cooling such crystals with liquid air permits the identification of upper stage bands based on one or two quanta of the bending frequency as well as the isotopic components of the “anti-symmetric” stretching mode due to ($N14C12O16$), ($N14C13O16)-$, ($N15C12O16$), and ($N14C12O18)-$, in their natural abundances, as well as ($N15C13O16)-$, etc, in $C13$ enriched samples. The constants for the anharmonic energy levels, including a Fermi Resonance, are being calculated along with the force constants; a qualitative discussion of the small but systematic shifts of the frequencies with host lattice will be given.”