Fermi Resonance in the Microwave Spectrum of LinearXYZMolecules

Abstract

Measurements of the rotation-interaction constants ${\alpha }_i$ for the various vibrational states in the microwave spectrum of OCS and OCSe show little consistency. These discrepancies are explained within experimental accuracy as being due to interaction between adjacent vibrational levels with quantum numbers $v_1$, $v_2$, $v_3$ and $v_1-1\mathrm{}$, $v_2+2\mathrm{}$, $v_3$. Resonance of this type, called Fermi resonance, has also been found in ICN but the interaction constant is very much smaller.