Abstract
We have investigated the vibrational coherence relaxation for the long‐living Ω(Ag) hybrid bound state of the Fermi diad ω1:2ω2 in natural crystalline CO2 at T≂5 K by means of time resolved nanosecond CARS spectroscopy. The decay profile was found to be slower than exponential and fitting reasonably well to an exp{−(t/τ)1/2} time dependence with τ=2.3±0.2 ns. Our results are discussed in terms of weak diagonal structural disorder upon the vibrational relaxation of exciton states located near the band edges.